MXPA00007736A - Quiet vacuum cleaner using a vacuum pump with a lobed chamber - Google Patents

Abstract

A vacuum cleaner has a vacuum pump with a housing (102) including a lobed chamber (104) having an epitrochoidal planform. The chamber has outlet ports (116o) and inlet ports (116i) in each lobe of the chamber, and a central stator gear (110). A triangular rotor (140) with curved sides is disposed for eccentric rotation in the chamber such that an inlet port and an outlet port in each lobe of the chamber are always in direct fluid communication during a portion of rotor travel, which prevents excessive pressure build-up at the chamber inlet ports, and a central rotor gear meshed with the stator gear. A drive disc (164) fits within a circular opening (149) in the rotor (140) and is mounted eccentrically to a drive shaft (162) driven by a motor to impart rotational motion to the rotor to generate air flow from the inlet ports (116i) to the outlet ports (116o) of the chamber (104). A ducting system connects the inlet ports of the chamber to a debris-collecting compartment. The vacuum cleaner supplies adequate cleaning power at lower rotational speeds and at lower air flow velocities, thus providing significant noise reduction.

Description

VACUUM CLEANER, SILENT, THAT USES A VACUUM PUMP WITH A LOBULATED CHAMBER Field of the Invention The present invention relates to a vacuum cleaner, and more particularly, to a vacuum cleaner that creates substantially less noise using a vacuum pump with a lobed chamber.

Description of Related Technology Although vacuum aspirators have become virtually indispensable, the noise they create limits their usefulness because other nearby activities frequently must cease during the application of the vacuum. There have already been many approaches to reducing the environmental noise of vacuum aspirators. One rather obvious is to incorporate a sound-insulating material in the vacuum cleaner housing. Although this approach somewhat reduces the level of noise around the vacuum cleaner, it does not actually attack at its source any of the noise generated by the vacuum cleaner. Another involves Ref.122405 the use of arrangements of silencers or dampers for the exhaust air flow. A more sophisticated approach to reducing exhaust or exit noise uses a noise detector at the outlet or exhaust of the vacuum cleaner to provide a signal used to generate a sound that cancels out the noise. A summary or selection of such approaches can be found in U.S. Pat. No. 4,418,443, No. 4,435,877, No. 4,512,713, No. 4,970,753, No. 5,502,869, No. 5,159,738, No. 5,499,423 and No. 5,513,417. However, none of these approaches attacks two appreciable sources of noise in a vacuum cleaner. One of these sources is the large flow velocities that must be generated by existing vacuum aspirators, to obtain a ratio or speed of mass that will provide effective cleaning. The other is the noise caused by the rotating components of the vacuum cleaner. According to well-known principles, the so-called "dipole noise", db, caused by the rotating components satisfies the relationship: Ndb? V (1) From equation (1) it can be seen that the noise of the dipole is proportional to the sixth power of the rotational speed? of the components generating the flow of a vacuum cleaner. Therefore, very small increases or decreases in the rotational speed will have a large effect on the dipole noise. The prior art approaches described above operate to mask the "jet noise" associated with the air stream exiting the vacuum cleaner housing. Approaches using shock absorber arrangements are generally observed to reduce the speed of the air stream before allowing it to exit the vacuum cleaner. This approach leads to a significant jet noise reduction because the jet noise is scaled or raised to the eighth power of the air flow velocity (ie, U8). Further noise reductions could still be possible if the velocity of the air flow exiting the vacuum cleaner drive was reduced. The present invention utilizes a positive displacement vacuum pump to reduce noise, and there are no known vacuum aspirators incorporating such a pump to create the pressure drop that produces the flow of entrained air from the waste in a vacuum cleaner. The reason for this lack in the prior art is most likely due to the mechanical complexity of most of the most common types of positive displacement pumps. For example, a pump that has a reciprocating piston could require complicated valve systems and fabricated parts to narrow tolerances. The cost of a vacuum cleaner incorporating such a pump would probably be much greater than what could be charged for a consumer product, and could be much less reliable than existing vacuum aspirators that simply use a rotary impeller. As a result, there are no known vacuum aspirators with a positive displacement pump of the Wankel type. Devices of the Wankel type were simply a curiosity until the problem of providing an adequate seal between the rotary "plunger" and the stationary "cylinder" walls was solved. Although solutions to these problems are now well known, they could probably be considered exotic for a product such as a vacuum aspirator. In any case, they could certainly raise the cost of a vacuum cleaner and could require frequent replacement because the compressor in a vacuum cleaner is subjected to abrasion of particulate matter entrained in the air flow.

Brief Description of the Invention It is an object of the present invention to provide a pump of the Wankel type suitable for use in a vacuum cleaner. It is another object of the present invention to provide a vacuum vacuum cleaner using a pump of the Wankel type and thereby substantially reduce the noise of the dipole generated during the operation of the vacuum cleaner and create a pressure drop and a rate or ratio of mass flow suitable for the lower fluid flow rates, whereby also the jet noise associated with conventional vacuum aspirators is reduced. It is still another object of the invention to provide a vacuum cleaner capable of generating a fluid flow of reduced pressure in which the material can be entrained for transport from one site to another, comprising a compartment for collecting the entrained matter, and a vacuum pump having a chamber with a plurality of lobes and a generally polygonal rotor with a plurality of sides in a number greater than the plurality of the lobes, the rotor is mounted for eccentric rotation within the lobed chamber to generate a reduced pressure in the lobes when the rotor rotates relative to the chamber, wherein the chamber is operatively connected to the compartment to induce the flow of fluid therethrough. In one embodiment of such a vacuum aspirator, the fluid is air and the chamber has a wing shape in the horizontal, epitrochoidal projection, which satisfies the equation x = (a + b) * cos (t) - c »cos ((a / b + l)« t), ey = (a + b) * sin (t) - c «sin ((a / b + l) * t), x and y are plotted or plotted from a center of the camera, where 0 < t < 2p, b / c = 2, ya / b = 2, whereby a chamber with two lobes is provided, and the rotor is generally triangular (ie, it is a regular polygon having (a / b + 1) sides) with the curved sides. According to a preferred embodiment of the present invention, a vacuum cleaner capable of generating a flow of air of reduced pressure in which the material can be dragged for transport from one place to another, comprises a compartment for collecting the entrained matter , the compartment has an inlet and an outlet for the air flow, a housing of the vacuum pump that includes a chamber with a wing shape in the horizontal, epitrochoidal projection, which satisfies the equation x = (a + b) »cos (t) - c * cos ((a / b + l)» t), ey = (a + b) »sin (t) - c * sin ((a / b + l) «t), x and y are plotted or plotted from a center of the camera, where 0 < t < 2p, a / b is an integer that defines the number of lobes in the chamber, and b / c = 2, the chamber has plural exit openings, at least one of the exit openings is placed in each of the lobes of the chamber, and multiple inlet openings, at least one of the inlet openings is placed in each of the lobes of the chamber, a stator gear in the chamber in the center thereof, the gear that has (a / b) * n teeth (n is a whole number), a one-piece rotor, usually polygonal, with (a / b + 1) curved sides, the rotor is placed for eccentric rotation in the chamber, where At least one inlet and one outlet in each lobe of the chamber are in direct fluid communication during a portion of the rotation of the rotor, a rotor gear in a center of the rotor, the rotor gear has (a / b + l) * n teeth, a cover mounted to the housing for enclosing the chamber, the seals on the opposite surfaces of the rotor facing the housing and the cover, a drive means including a disk that fits within a circular opening in the rotor and mounted eccentrically to a drive shaft to impart a rotary motion to the rotor to generate fluid flow from the inlet openings of the chamber to the outlet openings of the chamber, wherein the drive shaft passes through an opening in the cover coaxial with the stator gear, a pulse motor operatively connected to the pulse axis to impart a rotational movement thereto, and a system of conduits that operatively connect the openings Input of the chamber with the exit of the compartment to create a pressure drop from the entrance to the exit of the compartment. According to yet another aspect of the invention, a pump comprises a one-piece housing having a chamber therein with a wing shape in the horizontal, epitrochoidal projection, according to the equation x = (a + b) * cos (t) - c * cos ((a / b + l) »t), ey = (a + b) * sin (t) - c« sin ((a / b + l) * t), x and y are plotted or plotted from a camera center, where 0 <; t < 2p, a / b is an integer that defines the number of lobes in the camera, and b / c - 2, a stator gear in the camera in the center of it, the gear has (a / b) * n teeth ( n is a whole number), a one-piece rotor, usually polygonal, with (a / b + 1) curved sides, the rotor is placed for eccentric rotation in the chamber, a rotor gear in a center of the rotor, the The rotor gear has (a / b + l) »n teeth, a cover mounted to the housing for enclosing the chamber, and sealing means on the rotor to seal the rotor and housing during rotation of the rotor in the housing, the means Seals are constructed to allow a predetermined pressure drop across them.

Brief Description of the Drawings The objects of the invention will be better understood from the detailed description of their preferred embodiments which are given immediately, when taken in conjunction with the appended drawings, in which like reference numbers refer to similar characteristics of beginning to end The following is a brief identification of the Figures of the drawings used in the appended detailed description. Figure 1 is a schematic cross-sectional view of a vacuum cleaner of the conventional tank type incorporating a vacuum pump according to the present invention. Figure 2 is a schematic perspective view of a part of a vacuum vacuum cleaner of the conventional box type incorporating a vacuum pump according to the present invention. Figure 3 is a plan view of a vacuum pump device according to the present invention. Figure 4 is a cross-sectional view taken along line 4-4 in Figure 3. Figure 5 is a plan view of a first embodiment of a rotor for a vacuum pump according to the present invention. . Figure 6 is a plan view of a housing for a vacuum pump according to the present invention. Figure 7 is an exploded perspective view of a vacuum pump according to the present invention.

Figure 8 (a) is a plan view of a second embodiment of a rotor for a vacuum pump according to the present invention, and Figure 8 (b) is a sectional view taken along the line 8b -8a in Figure 8 (a). Figure 9 (a) is a plan view of another alternative embodiment of a rotor for a vacuum pump according to the present invention, and Figure 9 (b) is a sectional view taken along line 9b -9b of Figure 9 (a). Figure 10 is a plan view of yet another embodiment of a rotor for a vacuum pump according to the present invention. Figure 11 is a detailed view of an alternative embodiment of the invention showing a seal against leakage fixed to the housing of the vacuum pump.

Detailed Description of the Preferred Modalities Referring to Figure 1, a vacuum aspirator 20 of the conventional tank type is shown schematically (in partial cross section) having a generally cylindrical tank or compartment 22 that is resting freely on its lower end. An example of this type of vacuum aspirator is shown in detail in U.S. Pat. No. 4,435,877, and the manner of making and assembling it will be apparent from this patent by those skilled in the art. As explained in U.S. Pat. No. 4,435,877, a cover 24 is secured to the tank 22 by securing devices (not shown). An engine housing 26 is secured to the cover 24 by the screws 28. A cover 30 with a handle 32 is secured to the engine housing 26 in a suitable manner, as described in U.S. Pat. No. 4,435,877. A circular cage 34 is dependent on the cover 24 and supports a dust filter 36. An air inlet 38 is provided on the periphery of the tank 22. In a manner well known to those skilled in the art, an impeller mounted on the cover 24 applies a reduced pressure to an opening 40 in the cover near the axis of the tank 22. The inlet 38 is oriented to introduce the flow of air into the tank 22 in a generally circumferential direction. An air flow is therefore produced from the inlet 38, through the dust filter 36, through the opening 40, to a plenum 42 at the outlet of the impeller and eventually to an outlet or exhaust 44.

When the air charged with the dust and debris is drawn through the inlet for the air 38, it is directed circumferentially from the tank 22 so that a rotary air flow is established inside the tank 22. The angular momentum of the Air flow causes dust and heavier debris to collide on tank walls 22 and fall to the bottom. Near the central axis of the tank, where the opening 40 is located, the air is relatively free of dust. The filter 36 removes most of the residual dust, and air is then expelled from the impeller through the plenum chamber 42 to the exhaust port 40. The prior art known uses some type of fan as the impeller for such a vacuum cleaner . For example, U.S. Pat. No. 4,435,877 uses a cake type fan impeller in a shallow, round fan housing. In accordance with the present invention, a lobed vacuum pump 100 is used in place of the impellers used in the prior art. Such a vacuum pump according to the representative embodiments of the invention is described in more detail below. The present invention also comprises the use of a vacuum pump according to the present invention in other kinds of vacuum cleaners, such as vacuum vacuum cleaners of the vertical or box type. Figure 2 schematically shows part of a vacuum cleaner housing 50 of the conventional box type, incorporating a lobed vacuum pump device according to the present invention. An example of a vacuum vacuum cleaner of the type of box, more or less typical, is shown in U.S. Pat. No. 4,970,753, and the manner of making and assembling it will be apparent from this patent to those skilled in the art. As explained in U.S. Pat. No. 4,970,753, a lower wrapper portion 52 together with an upper portion (not shown) form an enclosure for the components of the vacuum cleaner. A compartment 54 for the dust collection receives a disposable filter bag 56 (shown with interrupted lines) that provides a container for the collection of the powder. An inlet 58 to the compartment 56 introduces the powder-laden air into an inlet 60 of the bag 56. In a manner well known to those skilled in the art, the bag 56 is made of a fabric material that allows air to pass but captures the particulate material dragged in the air. Vacuum cleaner 50 includes other conventional parts such as wheels 61 to help transport it and a handle 62 to carry it.

An exit from the compartment may comprise one or more outlet openings 63 in fluid communication with an impeller, which in the prior art is some type of fan, as in the vacuum cleaner described in relation to Figure 1. The fan creates a reduced pressure in the outlet openings 63, thereby creating a flow of air from the inlet 58, through the bag 56, to the outlet openings 63. The outlet or exhaust from the ventilator is directed through a series of plenums 64, and other suitable noise reducing devices if desired, to an outlet or exhaust opening 66. In accordance with the present invention, a vacuum pump of the Wankel 100 type is used in place of the impeller of the type of vacuum cleaner vacuum of the prior art. One embodiment of such a pump according to the present invention is shown in Figures 3 to 7. Figure 3 is a plan view of a vacuum pump 100 according to the present invention. The device includes a housing 102 that is constructed to form a chamber 104 having a plurality of lobes 106a and 106b. In a particularly advantageous embodiment of the invention, the housing 102 can be injection molded of a suitable plastic material, thus making possible the mass production of the housing and reducing the cost of the device. The reason that the housing can be made of a low strength material is that it is not necessary to support high pressures and does not have to be built to narrow tolerances to be used in a vacuum cleaner. The chamber 104 can very advantageously have a wing shape in the horizontal, epitrochoidal projection, according to the following equations defining an enclosure of the "classic" Wankel type: x = (a + b) «cos (t) - c» cos ((a / b + l) «t) (2) y = (a + b)» sin (t) - c »sin ((a / b + l) * t) (3) When 0 < t < 2p, b / c = 2, and a / b is an integer, these equations define a point site around an origin 0 (see Figure 6) located in the center of the camera. That is, the center of the camera is defined as the origin for the point site defined by equations (2) and (3). The value of a / b determines the number of lobes in the camera thus defined. In a preferred embodiment a / b = 2, but the camera can have any number of lobes according to the invention.

Chamber 104 extends toward one face of housing 102 to a depth d (see Figure 4). Molded integrally within the bottom 108 of the housing 102 is a circular stator gear 110 centered at the origin 0 of the curve defined by equations (2) and (3). (See Figure 6). The stator gear 110 has (a / b) * n teeth 112 (n is an integer). In the present embodiment a / b = 2 and n = 8, so that there are 16 teeth 112 on the stator gear 110. As with the number of lobes in the chamber, the number of teeth in the stator gear can be varied within the practice of the present invention by varying the value of n. The housing 102 also has molded therein two inlet conduits 114i and 116i and two outlet conduits 114o and 116o. The inlet and outlet conduits 114 and 116 provide flow paths from predetermined locations in each lobe 106 of chamber 104 for a purpose that will be clearer than the present methods of the description. The chamber 104 further includes a cover 118 secured to the face of the housing 102 within which the chamber 104 is formed. The cover 118 is fixed to the housing 102 by an adequate number of screws 120 which are tightened in blind holes 122 machined in the housing 102 after it is molded. A gasket or gasket 124 of a suitable material such as rubber is captured between the cover 118 and the housing 102 and is compressed during the assembly of the cover to the housing to make the chamber airtight. (Cover 118, the screws 120 and the gasket or gasket 124 are omitted from Figure 3 for reasons of clarity). It will be appreciated that any suitable sealant or arrangement material, such as one or more O-rings, may be used in place of or in addition to the gasket or gasket 124 to seal the cover 118 and the housing 102. In addition, other embodiments may be used. do without any such seals, because of the relatively low pressures at which the vacuum pump operates and the tolerance for small leakage quantities when the vacuum pump is used in a vacuum cleaner. The vacuum pump of the present invention also comprises a rotor 140, shown in detail in Figure 5. The rotor 140 is a regular polygon with a / b + 1 curved sides. In the present embodiment, the rotor 140 is generally triangular (a / b + 1 = 3). The configuration of the rotor 140 is designed to provide a desired compression ratio, say 5: 1, although other compression ratios are possible within the scope of the invention. That is, consistent with other operating requirements (see below), the curvature of the sides of the rotor is chosen so that the maximum volume of space between the rotor and the housing is a predetermined multiple of the minimum volume; in a preferred embodiment this multiple is approximately five. The rotor For the most part, it is also advantageously molded by injection in one piece from a suitable plastic material, or it can be cast or cast from a metal such as aluminum. An important consideration may be that the materials used to manufacture the housing and the rotor will prevent or inhibit bonding when the rotor travels within the housing, depending on the sealing arrangement used (as described below). The rotor 140 has a central circular opening 141 through it. A portion of the axial extension of the opening 141 includes a rotor gear. The opening 141 has a center C at the geometric center of the regular polygon comprising the rotor. If the rotor is injection molded, the opening is molded with the rotor gear in place to provide a one-piece rotor. As best seen in Figure 3, the teeth 142 of the rotor gear engage or mesh with the stator gear 110 to control the rotation of the rotor 140 within the chamber 104. The rotor gear has (a / b + l ) * n teeth. Since n = 8 in the present embodiment, the rotor gear 144 has 24 teeth. The teeth 142 of the rotor gear are curved to form convexly curved gear teeth, which are joined or abutted closely with the generally corresponding concavely curved teeth 112 on the stator gear 110. This arrangement provides a more positive angular positioning. of the rotor 140 when it travels through the chamber 104. The rotor 140 is also molded with a notch 146 on each side (see also Figure 4). Each notch 146 is continuous and at its full length is spaced the same distance from the edge of the rotor. Each notch carries a flexible seal 148 made of a suitable material such as felt, rubber, aluminum, plastic or any other material that will easily slide over and will not be bonded with the material used to manufacture the housing 102 and the cover 118, since seal 148 rests against bottom 108 (see Figure 4). The notch 146 on each face approaches the edge of the rotor in the vicinity of each vertex of the polygonal rotor. By controlling how closely the notch is relative to the edge of the vertices, the pressure drop across the seals can be controlled according to a feature of the invention described in greater detail below. The manner of driving the rotor will be better appreciated from Figures 3, 4, and 7 taken together. The rotor 140 is driven in an eccentric rotary motion within the housing 102 by a pulse element 160. The drive member comprises a drive shaft 162 connected to the shaft of an electric motor 200 (see FIGS. 1 and 2). The drive shaft carries a round disk 164 mounted eccentrically, rigidly secured to the drive shaft with the center of the circular disk 164 offset from the axis of the shaft or drive shaft at a distance e (see FIG. 3). That is, those skilled in the art will appreciate that for the compressor device 100 to operate properly, the center C of the rotor gear must subscribe a circle with a radius e about the center O of the stator gear. To provide such rotation, the drive shaft 162 is mounted coaxially with the center O of the stator gear in a plain bearing 166 in the cover 118. The pulse disk 164 is positioned within the axial extension 149 of the central opening of the rotor 141 not occupied by the rotor gear. Accordingly, when the drive disk rotates, the rotor 140 travels inside the chamber 104 with the appropriate eccentric movement. The drive disk is made of a material that readily allows relative movement between itself and the rotor when the drive disk pushes the rotor into the chamber. The vacuum pump 100 is provided in a vacuum cleaner such as the vacuum cleaner of the tank type 20 shown in Figure 1 or the vacuum cleaner of the box type shown in Figure 2, using a duct system that fixes the intake openings 114i and 116i to the outlet of the dust collecting chamber. Specifically, the tank type vacuum aspirator 20 shown in Figure 1 includes a manifold 300 that fits between the housing 102 and the opening 40. The manifold 300 has at one end a central opening (not shown) that opens toward the opening 40. The openings (not shown) connect the interior of the manifold 300 with the intake openings 114i and 116i of the chamber 104. As seen in Figure 4, the housing 102 is molded with the intake openings leading out towards the housing 102 on one of its faces, so that the intake openings are in direct communication with the interior of the manifold. The outlet openings 114o and 166o may also be molded to exit from the housing 102 at any convenient location, but in this embodiment they exit from the face of the housing edge 102, as shown in Figures 3 and 4, toward the bladder 42. The box type vacuum cleaner 50 shown in Figure 2 also includes a manifold 302 communicating with the compartment 54 through the openings 63. The intake openings 114i and 116i of the compressor device of the present invention they communicate directly with the manifold 302 when the vacuum pump 100 is assembled in the vacuum cleaner 50. The outlet openings 114o and 116o of the device 100 lead directly to the outlet or exhaust plenum 64. In the operation the drive shaft 162 is operatively connected to the motor 200 in a suitable manner (described in greater detail below) and rotates the rotor 140 in the direction of the arrow A in Figure 3. When the rotor 146 rotates, it creates with the chamber 104 four volumes, two in each lobe 106a and 106b. Each volume first expands to extract air through one of the inlet openings 114i and 116i, and then one corner of the rotor passes to each inlet opening and each volume is then reduced (in a ratio of approximately 5: 1, as described above), which forces the air in this volume out of one of the outlet openings 116o and 114o, respectively. In this way, the pump creates a drop in pressure between its inlet and outlet openings to remove the air laden with dust and dirt through the vacuum cleaner in which it is installed. A major advantage of the present invention is that it makes possible pressure drops ("voids") comparable with those in conventional vacuum aspirators with rotary speeds of a fraction of those required in such conventional units. For example, the speed? of the rotary parts in conventional vacuum aspirators can be as high as 28,000 to 32,000 rpm (see U.S. Patent No. 5,159,738). A vacuum cleaner with the compressor device of the present invention can operate at an angular velocity? of a magnitude of approximately 5000 rpm. Since the noise of the dipole is proportional to? 6, it will be appreciated that the possible reduction of noise with the present invention is significant. Seen otherwise, the industry standard measurement of vacuum cleaner operation is called "pneumatic watt", which is the speed of mass flow through the vacuum cleaner multiplied by the pressure drop? Pa through of the unit driver. Since the compressor device of the present invention is capable of generating a much higher? P for an angular velocity, it can provide a vacuum cleaner with the same evaluation of power in pneumatic watts at a much lower rotational speed. The motor shaft 200 is fixed to the shaft 162 of the pulse element 160 by a flexible coupling, preferably a hollow rubber tube (not shown). The motor is mounted on the vacuum cleaner with absorbing mounts of shock or shock to isolate the housing from the vibrations of the motor. This isolation of the vibration is improved by the flexible coupling between the compressor device and the motor. In consecuense, the vacuum cleaner can be made quieter. In a typical device according to the present invention, the housing is molded in one piece and is 30 mm thick and circular in the shape of the wing in the horizontal, epitrochoidal projection, with a diameter of 200 mm. The depth d of the camera is 25 mm. The stator gear has an external diameter (measured through the upper parts of the gear teeth) of 42.15 mm, and each gear tooth is concave circularly with a diameter of 7.00 mm. The rotor is molded in one piece and measures 125 mm from apex to apex and the curved sides have a radius of 160 mm. The rotor is 24 mm thick, and the circular opening that has the rotor gear is 70 mm in diameter. The teeth of gear of the rotor are surrounded in their ends to a radius of 1.5 mm. With such a device rotating in the direction of arrow A in Figure 3 at a speed of approximately 5000 rpm, a pressure drop of approximately 0.1 atmospheres is generated. This is in excess of the pressure drop usually provided by conventional vacuum aspirators, thereby reducing the flow velocity of the mass (and the air flow rate) necessary to provide the same amount of power in pneumatic watts. It will be appreciated by those skilled in the art that other dimensions and configurations of the compressor device can be used to provide the desired mass flow velocity and pressure drop. The rotor configuration is chosen to provide a predetermined spacing between the curved sides of the rotor and the narrow portion of the chamber 104 separating the lobes 106a and 106b. It is important in the present invention that such spacing be as small as possible so that fluid communication between the chambers defined by the lobes is minimized when the rotor rotates. The size of the spacing is determined by the appropriate choice of the radius of curvature of the sides of the rotor relative to the dimensions of the chamber.

If this spacing is too large, it will adversely affect the operation of the pump because there will be excessive fluid flow between the chambers, and consequently an undesirable communication between the input 116i and the output 116o and the input 114i and the exit 114o. If desired, the leakage seals 300 may be added to the housing to further inhibit this fluid communication. Such seal according to an alternative embodiment of the invention is shown in Figure 11, which is an enlarged view of the lower portion of the housing 102 (as seen in Figure 3) where the lobes 106a and 106b are joined. The seal against leakage in this embodiment is a small spring steel clamp 302. One end 304 of the clamp fits or fits into a slot 102x in the housing and the other end 306 of the clamp fits or fits into a slot 102and in the accommodation. The central portion 308 of the clip is slightly bulged outwardly inside the chamber, so that the rotor will slide above the clip when the same rotates inside the housing. Another seal against leakage could be provided in the upper portion of the housing where the lobes 106a and 106b are joined.

The device of the present invention is a positive displacement compressor, so that an obstruction in the intake of the device will lead to a significantly increased pressure drop, unlike conventional vacuum aspirators. If not taken into account, this could be potentially dangerous because the obstruction in the intake could be an object at the end of the hose used to absorb the waste and debris that is cleaned by the vacuum cleaner. If this obstruction was a fragile item, such as draperies or a lamp, or a pet or small child, serious damage or breakage could result. Therefore, it is an important feature of this embodiment of the present invention that the entrance opening 114i and the exit opening 116o of the lobe 106a, and the entry opening 116i and the exit opening 114o of the lobe 106b, are located so that during at least a part of the rotor path the inlet opening and the outlet opening for each lobe are in direct communication. This is shown by the location of the dashed lines of the rotor 140 shown in Figure 3. In this way, the drop in pressure that can be generated is limited because the input and the output will always be in communication.

----- «----------------- ^ --------- My ------ of direct fluid during at least part of the way of the rotor. Those skilled in the art will appreciate that the vacuum pump of the present invention may utilize different sealing arrangements than the flexible seal 148 of felt or the like in the above embodiment. Figures 8 (a) and 8 (b) show an alternative embodiment of a rotor incorporating an integral seal suitable for use in the present invention. The rotor 140 'shown in FIG. 8 has raised seals 248 integrally molded on their faces, instead of having a strip seal similar to the seal 148 carried in the notches 146 as shown in the previous embodiment. The raised seals 248 are generally rounded on the upper surface and provide a slight spacing between the rotor and the housing (and the cover) so that the small particulate material entrained in the fluid can be passed through the seals without subjecting them to abrasion. The rotor 140 'is especially useful when the pump of the present invention is used to move liquids other than air. An advantage of this embodiment is that the seal 248 can be placed closer to the end of the rotor at the vertices of the rotor, and the sealing cross-section can still be profiled to more accurately control the pressure drop across the rotor. same Figure 8 (b) shows a seal with a generally semicircular cross section, but other cross sections that represent more or less of a circle, or even assuming a non-circular configuration, or a configuration that changes along the length of the seal, may be adopted. Figures 9 (a) and 9 (b) show another alternative embodiment of a sealing arrangement according to the present invention. The rotor 140"according to the present embodiment has a cutout 150 in the shape of a lock (only one of which is shown in Figure 9.) The cutout 150 has placed therein a sealing element 250 of the tip or vertex. The tip or vertex sealing element includes an enlarged body portion 252 that fits relatively tightly within the cutout 150 of the inner portion and an integral tongue 254 extending through the leg of the lock cutout 150. and beyond the tip or vertex of the rotor 140". The rotor 140"includes notches 146" corresponding to the notches 146 in the first embodiment described above. However, in the present embodiment the notches can be made equidistant from the edges of the rotor from beginning to end of the length of the notch. The faces of the sealing element 250 also include the notches 256 which are in alignment with the notches 146. The seals 148 (shown with dashed lines in Figure 9 (b)) fit or fit into the notches 146"as in FIG. previous embodiment, and also in the notches 256 in the sealing element 250. The sealing element 250 of the tip or apex extending beyond the faces of the rotor 140", as seen in Figure 9 (b), it will be level with the sealing surface of the peripheral seals 148. The seals 148 themselves interfere with the sealing element 250, and since the seals are flexible, they allow the sealing element 250 of the tip or vertex to be move in the directions of the arrow B when the rotor travels inside the housing It will be appreciated that the sealing element 250 of the tip or vertex will be "deflected" to its outermost position by the flexible seals 148 so that it is in a Contact more positive with the walls of the chamber 104 from beginning to end of the travel of the rotor in the housing (see Figure 3). The end of the tongue 254 of the tip or vertex sealing element will typically be slightly curved to conform more closely to the inner surfaces of the lobes 106a and 106b, whereby a more effective seal is provided when the rotor travels within the housing 102. In addition, the sealing element 250 can be made of a material that is softer than the material used for the housing so that the tip of the tongue 254 is worn in its shape that will conform more closely to the internal contour of the tongue. the chamber 104. In any case, the present embodiment has the advantage of providing a more positive seal, which can be particularly advantageous when the device of the present invention is used for applications other than a vacuum cleaner for the consumer. That is, although this sealing arrangement is more complex, it also provides a better seal and can be replaced when worn by the particulate matter entrained in the fluid that is moved by the device. It also has the advantage of allowing the use of the optimum material for the sealing elements 148 and 250 and therefore allows a larger margin in the materials used for the housing 102 and the rotor 140. Figure 10 shows a variation of the embodiment shown in Figure 9. In Figure 10, the lock cutout 150 is replaced by a slot 150 'with the straight sides, and the sealing element 250' of the tip or apex is configured to fit within the slot 150. ' Seal member 250 'may be biased outwardly by a small compression spring (not shown) at the root of the slot. (It will be appreciated that a spring can be used for the same purpose in the embodiment of Figure 9). The embodiment in Figure 10 has the advantage of being easier to manufacture than the embodiment of Figure 9., although the sealing element of the tip or vertex is not retained either. From the above description it will be clear that the present invention is suitable for use in environments other than a vacuum cleaner. It is particularly useful for pumping with entrained particulate material because it is a feature of the invention not to include the elaborate sealing arrangements found in prior art Wankel-type devices that must withstand extremely large pressure drops at through the stamps. In contrast, the present invention uses sealing means made specifically to allow flow through the seals at a predetermined pressure drop. Examples of the sealing structure that performs the function of allowing a predetermined pressure drop are as described above, but any sealing structure that performs such a function is within the scope of the present invention. Examples other than those described and illustrated specifically could include C-shaped spring clips at the tips or vertices of the rotor, with the legs of the spring clips placed in the slots in the? faces of the edges of the rotor and the intermediate portion of the spring clips in contact with the walls of the chamber 104. Another example of such a seal could involve having a portion of reduced thickness at each tip or apex of the rotor to provide a flexible portion integral with the rotor. Such arrangements could be used with face seals similar to those already described with the sealing structure of the alternative face. In summary, the present invention in its broad aspects involves a pumping device of the Wankel type which is especially suitable for use with fluids in which the particulate matter is entrained. The Wankel type device of the present invention utilizes the seals which, unlike those used in prior art Wankel type devices, are specifically constructed to allow a predetermined pressure drop (and therefore a predetermined amount of pressure). fluid flow) through the seal. By incorporating such seals into the device, the seals do not need to be manufactured to narrow tolerances using expensive materials and with exotic configurations; instead, seals can be made economically from sturdy materials to provide a long seal life even in highly abrasive environments. One such means for which the present invention is particularly suitable is a vacuum aspirator. Even if the pumping device of the Wankel type of the invention is used in a dirty, sandy environment, it can be made economical enough and will not require more maintenance than a conventional vacuum cleaner. Although preferred embodiments of the invention have been shown and described, it will be understood that various changes and modifications may be made other than those specifically mentioned above without departing from the spirit and scope of the invention, which is defined solely by the claims that follow It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following

Claims (24)

1. A vacuum cleaner capable of generating a fluid flow of reduced pressure in which a material can be dragged for transport from one location to another, the vacuum cleaner is characterized in that it comprises: a compartment for collecting the entrained matter; and a vacuum pump having a chamber with a plurality of lobes and a generally polygonal rotor with a plurality of sides larger in number than the plurality of lobes, the rotor is mounted for eccentric rotation within the lobed chamber to generate a reduced pressure in the lobes when the rotor rotates relative to the chamber, wherein the chamber is operatively connected to the compartment to induce the flow of fluid therethrough.

2. A vacuum aspirator according to claim 1, characterized in that: the chamber has a wing shape in the horizontal, epitrochoidal projection, which satisfies the equation x = (a + b) «cos (t) - c» cos (( a / b + l) * t), ey = (a + b) * sin (t) - c * sin ((a / b + l) * t), x and y are plotted or plotted from a center of the camera, where 0 < t < 2p, a / b is an integer that defines the number of lobes in the camera, and b / c = 2; and the rotor is a regular polygon that has (a / b + 1) curved sides.

3. A vacuum cleaner according to claim 2, characterized in that the fluid is air and a / b = 2.

4. A vacuum cleaner according to claim 3, characterized in that the compartment includes an inlet and an outlet for the air flow, the vacuum cleaner further comprises a system of ducts that operatively connect the chamber to the outlet of the compartment to create a pressure drop from the entrance to the exit of the compartment.

5. A vacuum aspirator according to claim 4, characterized in that: the compartment is constructed to receive a collecting container made of a material that allows the flow of air to pass through it and captures the particulate material entrained in the air flow; the compartment entrance is constructed to introduce the flow of air into a container inlet; and the outlet of the compartment is positioned in relation to the inlet to induce the flow of air through the compartment and through it through the container.

6. A vacuum cleaner according to claim 4, characterized in that: the compartment is a generally cylindrical tank; the compartment inlet is positioned at the periphery of the tank and is oriented to introduce the flow of air to the tank in a generally circumferential direction thereof; and the outlet of the compartment is positioned proximate a tank axis at one end thereof and is oriented to extract the flow of air from the tank in a generally axial direction.

7. A vacuum cleaner according to claim 1, characterized in that: the chamber includes at least two outlet openings, each of the lobes of the chamber has at least one of the outlet openings placed therein; the chamber includes at least two entry openings, each of the lobes of the chamber having at least one of the entry openings placed therein; and at least one of the inlet opening and one of the outlet opening in different lobes of the chamber are in direct fluid communication during a portion of the rotation of the rotor.

8. A vacuum cleaner capable of generating a flow of air of reduced pressure in which the material can be dragged for transport from one place to another, the vacuum cleaner is characterized because it comprises: a compartment for collecting the entrained matter, the compartment it has an entrance and an exit for the air flow; a housing of the vacuum pump that includes a chamber with a wing shape in the horizontal, epitrochoidal projection, which satisfies the equation x = (a + b) «cos (t) - c« cos ((a / b + l ) »T), ey = (a + b) * sin (t) - c» sin ((a / b + l) «t), x and y are plotted or plotted from a center of the camera, where 0 <; t < 2p, a / b is an integer that defines the number of lobes of the chamber, and b / c = 2, each of the lobes of the chamber has at least one exit opening and an entry opening placed therein; a stator gear in the chamber at a center thereof, the stator gear has (a / b) * n teeth, where n is an integer; a one-piece rotor, usually polygonal, with (a / b +1) curved sides, the rotor is positioned for eccentric rotation in the chamber; a rotor gear in a center of the rotor, the rotor gear is spliced or meshed with the stator gear and has (a / b + l) * n teeth; a cover mounted to the housing to enclose the chamber; an impulse means including a disk that fits or fits within a circular opening in the rotor and mounted eccentrically to a pulse shaft to impart rotary motion to the rotor to generate a fluid flow from the inlet openings of the chamber to the outlet openings of the chamber, wherein the drive shaft passes through an opening in the cover coaxial with the stator gear; an impulse motor operatively connected to the drive shaft to impart a rotational movement thereto; and a duct system that operatively connects the inlet openings of the chamber with the outlet of the compartment to create a pressure drop from the inlet to the outlet of the compartment.

9. A vacuum cleaner according to claim 8, characterized in that: a / b = 2; the compartment is constructed to receive a collecting container made of a material that allows the flow of air to pass through it and captures the particulate material entrained in the air flow; the entrance of said compartment is constructed to introduce the flow of air towards an entrance of the container; and the outlet of the compartment is positioned relative to the inlet to induce the flow of air through the compartment and through this through the container.

10. A vacuum cleaner according to claim 8, characterized in that: the compartment is a generally cylindrical tank; the compartment inlet is positioned at the periphery of the tank and is oriented to introduce the flow of air to the tank in a generally circumferential direction thereof; and the outlet of the compartment is positioned proximate a tank axis at one end thereof and is oriented to extract the flow of air from the tank in a generally axial direction.

11. A vacuum cleaner capable of generating a fluid flow of reduced pressure in which the material can be dragged for transport from one place to another, the vacuum cleaner is characterized by comprising: a compartment to collect the entrained material, the compartment it has an inlet and an outlet for fluid flow, a housing for the vacuum pump having a chamber with a plurality of lobes, each of the lobes of the chamber having at least one outlet opening and an inlet opening placed in them; a stator gear in the chamber in a center thereof; a rotor with a plurality of sides greater in number than the plurality of lobes, the rotor is positioned for eccentric rotation in the chamber to generate a reduced pressure in the lobes when the rotor rotates relative to the chamber; a rotor gear in a center of the rotor that is engaged or spliced with the stator gear; and an impulse element for imparting a rotary movement to the rotor to generate a flow of fluid from the inlet openings of the chamber to the outlet openings of the chamber, the inlet openings of the chamber are operatively connected to the outlet of the chamber to create a pressure drop from the entrance to the exit, from the compartment.

12. A vacuum aspirator according to claim 11, characterized in that the rotor includes sealing means for sealing the rotor and the chamber during rotation of the rotor in the chamber, the sealing means being constructed to allow the flow of the fluid to pass through the chamber. the sealing means at a predetermined pressure drop therethrough.

13. A vacuum cleaner according to claim 12, characterized in that the sealing means comprise the tips or vertices of the rotor that are spaced from the walls of the chamber to maintain a spacing between the tips or vertices and the walls when the rotor rotates in the chamber, to allow the flow of fluid through the gap or spacing.

14. A vacuum cleaner according to claim 12, characterized in that the sealing means comprise seals maintained in contact with the tips or vertices of the rotor and the walls of the chamber when the rotor rotates in the chamber.

15. A pump for moving the fluid, the pump is characterized in that it comprises: a housing having faces and a circumferential wall forming a chamber with a plurality of lobes; a stator gear in the chamber at a center thereof, a generally polygonal rotor with a plurality of sides larger in number than the plurality of the lobes, the rotor is positioned in the lobed chamber with the rotor faces opposite the faces of the housing for the unrestricted movement of the faces of the rotor relative to the faces of the housing; a rotor gear in a rotor center meshed with the stator gear, and a pulse element for imparting an eccentric rotary motion to the rotor inside the chamber to generate a reduced pressure in the lobes when the rotor rotates relative to the chamber , wherein the tips or vertices of the rotor are spaced from the wall of the housing and have no sealing elements to contact the wall, whereby a spacing between the tips or vertices and the wall is maintained when the rotor rotates in the chamber to allow the flow of fluid through the gap or spacing.

16. A pump according to claim 15, characterized in that the rotor is molded in one piece.

17. A pump according to claim 16, characterized in that the housing is molded in one piece.

18. A pump according to claim 15, characterized in that it also comprises a seal that extends around the rotor on at least one face thereof.

19. A pump according to claim 18, characterized in that the rotor is molded in one piece and each of the face seals includes a projection molded on the face of the rotor.

20. A pump according to claim 15, characterized in that: the chamber includes at least two outlet openings, each of the lobes of the chamber has at least one of the outlet openings placed therein; the chamber includes at least two entry openings, each of the lobes of the chamber having at least one of the entrance openings placed therein; and at least one of the inlet openings and one of the outlet openings in different lobes of the chamber are in direct fluid communication during a portion of the rotation of the rotor.

21. A vacuum pump capable of generating a fluid flow of reduced pressure in which a particulate material is entrained, the vacuum pump is characterized in that it comprises: a pump housing having faces and a circumferential wall forming a chamber with a plurality of lobes, each of the lobes of the chamber has at least one exit opening and at least one entry opening placed therein; a stator gear in the chamber in a center thereof; a rotor with a plurality of sides greater in number than the plurality of the lobes, the rotor is placed in the lobed chamber with the rotor faces opposite the faces of the housing for the unrestricted movement of the faces of the rotor relative to the faces of the housing; a rotor gear in a center of the rotor engaged with the stator gear; and a pulse element for imparting an eccentric rotating motion to the rotor within the chamber to generate a reduced pressure in the lobes when the rotor rotates relative to the chamber to produce fluid flow from the chamber inlet opening to the chamber. the outlet opening of the chamber, wherein the tips or vertices of the rotor are spaced from the wall of the housing and the tips or vertices do not have sealing elements for contact with the wall, whereby a spacing between the tips is maintained or vertices and the wall when the rotor rotates in the chamber to allow fluid flow through the gap or spacing.

22. A vacuum pump according to claim 21, characterized in that: the drive element includes a disk that fits within a circular opening in one of the faces of the rotor and mounted eccentrically to a drive shaft, the circular opening is coaxial with the rotor gear; and the driving shaft passes through a hole in a cover fixed to the housing forming one of the faces thereof, the hole is coaxial with the stator gear.

23. A vacuum pump according to claim 22, characterized in that the chamber has a wing shape in the horizontal, epitrochoidal projection, which satisfies the equation x = (a + b) * cos (t) - c »cos ((a / b + l) »t), ey = (a + b) * sin (t) - c * sin ((a / b + l) * t), x and y are plotted or plotted from a center of the camera, in where 0 < t < 2p, a / b is an integer that defines the number of lobes in the camera, and b / c = 2; the stator gear has (a / b) »n teeth, where n is an integer; and the rotor has a wing shape in the horizontal, epitrochoidal, generally polygonal projection that has (a / b + 1) curved sides.

24. A pump according to claim 23, characterized in that: a / b = 2 to provide two of the lobes separated by opposite narrow portions; and the rotor is configured so that a spacing to allow fluid flow therethrough is maintained between the sides thereof and the narrow portions of the chamber when the rotor rotates in the chamber. SUMMARY OF THE INVENTION The present invention relates to a vacuum aspirator having a vacuum pump with a housing (102) including a lobed chamber (104) having a wing shape in the horizontal, epitrochoidal projection. The chamber has exit openings (116o) and inlet openings (116i) in each lobe of the chamber, and a central stator gear (110). A triangular rotor (140) with curved sides is positioned for eccentric rotation in the chamber such that an inlet opening and an outlet opening in each lobe of the chamber are always in direct fluid communication during a portion of travel of the chamber. rotor, which prevents excessive pressure from accumulating in the inlet openings of the chamber, and a central rotor gear geared to the stator gear. A pulse disk (164) fits within a circular aperture (149) in the rotor (140) and is eccentrically mounted to a pulse shaft (162) driven by a motor to impart rotary motion to the rotor to generate a flow of air from the inlet openings (116i) to the outlet openings (116o) of the chamber (104). The duct system connects the inlet openings of the chamber to a waste collection compartment. The vacuum cleaner provides adequate cleaning or suction power at lower rotating speeds, thus providing a significant reduction in noise. t ^ ^ _