Patent Publication Number: US-7900315-B2

Title: Integrated central vacuum cleaner suction device and control

Description:
FIELD OF THE INVENTION 
     The invention relates to suction devices for central vacuum cleaning systems. 
     BACKGROUND OF THE INVENTION 
     Central vacuum cleaning systems were originally quite simple. One placed a powerful central vacuum source external to the main living space. The source was connected through interior walls to a long flexible hose that terminated in a handle and nozzle. When an operator desired to use the system, the operator went to the source and turned it on. The operator then went inside, picked up the handle and directed the nozzle to an area to be cleaned. 
     Although many elements of the basic system remain, many improvements have been made. Rigid pipes typically run inside interior walls to numerous wall valves spaced throughout a building. This allows an operator to utilize a smaller hose while covering an equivalent space. This is an advantage as the hose can be quite bulky and heavy. 
     Various communication systems have been developed. Some systems sense sound or pressure in the pipes to turn the vacuum source on or off, see for example U.S. Pat. No. 5,924,164 issued 20 Jul. 1999 to Edward W. Lindsay under title ACOUSTIC COMMUNICATOR FOR CENTRAL VACUUM CLEANERS. Other systems run low voltage wires between the source and the wall valve. The source can be turned on and off at a wall valve by a switch that may be activated by insertion or removal of the hose. The hose may also contain low voltage wires to allow the source to be controlled from a switch in the handle, see for example U.S. Pat. No. 5,343,590 issued 6 Sep. 1994 to Kurtis R. Radabaugh under title LOW VOLTAGE CENTRAL VACUUM CONTROL HANDLE WITH AN AIR FLOW SENSOR. The switch can be a simple toggle switch, or a more sophisticated capacitive switch. 
     The low voltage wires running along the pipes can be replaced by conductive tape or the like on the pipes, see for example U.S. Pat. No. 4,854,887 issued 8 Aug. 1989 to Jean-Claude Blandin under title PIPE SYSTEM FOR CENTRAL SUCTION CLEANING INSTALLATION. Separate low voltage conductors in the walls can be avoided altogether by home using mains power wires to transmit communication signals between the wall valve and the source, see for example U.S. Pat. No. 5,274,878 issued 4 Jan. 1994 to Kurtis R. Radabaugh et al under title REMOTE CONTROL SYSTEM FOR CENTRAL VACUUM SYSTEMS. A handheld radio frequency wireless transmitter can be used by an operator to turn the source on or off, see for example U.S. Pat. No. 3,626,545 issued 14 Dec. 1971 to Perry W. Sparrow under title CENTRAL VACUUM CLEANER WITH REMOTE CONTROL. 
     Line voltage can be brought adjacent the vacuum wall valves and connected to the handle through separate conductors, or integrated spiral wound conductors on the hose. Line voltage can then be brought from the handle to powered accessories, such as an electrically-powered beater bar, connected to the nozzle. Line voltage can be switched on and off to the powered accessory using the same switch in the handle that controls the source. Alternatively, the powered accessory may have its own power switch. 
     A control module mounted to the central vacuum unit is typically used to control the vacuum source. As central vacuum cleaning systems have become more and more sophisticated, so has the control module. 
     Improvements to, or additional or alternative features for, central vacuum cleaning systems are desirable. 
     SUMMARY OF THE INVENTION 
     In a first aspect the invention provides an apparatus for use in a central vacuum cleaner unit. The device includes a high speed suction device having a cooling section, a motor section, and a suction section, and includes a control module. The motor section drives the suction section to draw vacuum air. The motor section drives the cooling section to provide cooling air for cooling the motor section. The control module controls power to the motor section. The control module and suction device are integrally mounted as a single unit. 
     The control module may be mounted in a path of the cooling air after the motor section. The control module may be affixed to the suction device. The control module may include a vibration sensor for sensing vibrations from the suction device. The control module may include a temperature sensor for sensing temperature of the suction device. The control module may include at least one environmental condition sensor for sensing at least one environmental condition of the suction device. 
     In a second aspect the invention provides a central vacuum unit for use in a central vacuum cleaning system. The unit includes the apparatus of the first aspect, a motor chamber, and a suction chamber. The apparatus is mounted such that vacuum air is drawn through the suction chamber by the suction section and cooling air is drawn through the motor chamber by the cooling section. 
     In a third aspect the invention provides a central vacuum cleaning system including the central vacuum unit of the second aspect, a handle, at least one wall valve, vacuum hose for connection between the handle and the wall valve, and piping for connection between the at least one wall valve and the central vacuum unit. 
     Other aspects of the invention will be evident from the principles contained in the description and drawings herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present invention and to show more were clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show the preferred embodiment of the present invention and in which: 
         FIG. 1  is a top of view of an apparatus in accordance with a preferred embodiment of the present invention. 
         FIG. 2  is a perspective view of the apparatus of  FIG. 1 . 
         FIG. 3  is a side view of the apparatus of  FIG. 1  cut-away along the line A-A′ of  FIG. 1 . 
         FIG. 4  is a perspective view of a control module used in the apparatus of  FIG. 1 . 
         FIG. 5  is a side cross-section view of a preferred embodiment of a central vacuum unit containing the apparatus as shown in  FIG. 4 . 
         FIG. 6  is a block diagram of a preferred embodiment of a control circuit for a central vacuum unit containing the apparatus of  FIG. 1 . 
         FIG. 7  is a side cross-section of a dwelling with a preferred embodiment of a central vacuum system incorporating the unit of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the FIGS., an integrated apparatus  1  has a suction device with a cooling section  3 , a motor section  5 , a suction section  7 . The apparatus  1  also has a control module  8 . The motor section  5  drives the suction section  7  to draw vacuum air, as shown by arrows  9 , through inlet  11  and exhaust vacuum air through outlet  13 . The motor section  5  also drives the cooling section  3  to draw cooling air, as shown by arrows  15 , through cooling air inlet  17  and push it through the motor section  5 , as shown by arrows  19 , to cool the motor section  5 . 
     The control module  8  controls the operation of the motor section  5 . The control module  8  is located in the cooling air path after the motor section  5 , as indicated by arrows  21 . The cooling air for the motor section  5  also cools the control module  8 . 
     The cooling section  3 , motor section  5 , suction section  7  and control module  8  are integrally mounted to form a single unit. This allows a designer of the apparatus  1  to ensure that components of the apparatus  1  are properly matched. It also allows the apparatus  1  to be certified as a whole. A central vacuum manufacturer will not need to obtain its own certification for a central vacuum unit in addition to a certification obtained for the apparatus  1  and the control module  8 . Typically, a central vacuum manufacturer must obtain its own certification for the central vacuum unit as the separate mounting of a control and a motor in a central vacuum unit creates a device separate from the control and the motor for regulatory purposes. 
     Referring to  FIG. 3 , the motor section  5  in central vacuum applications is typically a universal motor having a commutator  31 , rotor  33  and stator  35 . The rotor  33  has rotor laminations  37  and rotor windings  39 . The stator  35  has stator laminations  41  and stator windings  43 . The rotor windings  39  and the stator windings, not shown, are powered through the commutator  31 . 
     The rotor  33  is mounted on a shaft  51  such that rotation of the rotor  33  causes the shaft  51  to rotate. 
     A universal motor is typically used in central vacuum applications to obtain the high speeds necessary for adequate suction. The principles described herein can be applied to other motors for central vacuum applications to the extent that such motors require a separate control module or that such motors require an air driven cooling section. 
     The cooling section  3  utilizes the shaft  51  and a set of rotary fan blades  53  to drive the cooling air. The fan blades  53  rotate with the shaft  51 . 
     The suction section  7  will typically use a multi-stage impeller  55  mounted on the shaft  51 . As the shaft  51  rotates the impeller  55  rotates and draws vacuum air  9  through the apparatus  1 . As is known in the art, other suction sections  7  could be used. 
     Referring to  FIG. 4  the control module  8  has a printed circuit board  70  and a heat sink  71 . Components, indicated generally by  73 , used in the control module  8  are mounted on the printed circuit board  70 . Some components, for example power integrated circuits  75 , are also mounted to the heat sink  71 . These components  75 , particularly when placed in a partially enclosed environment with other heat producing sources, require the additional cooling heat sink  71  can provide. As the control module  8  is in the cooling air path, the heat sink  71  can typically be smaller than a heat sink that is used for a control module mounted to the central vacuum unit housing as is known in the art. 
     Access through the printed circuit board  70  for mounting the components  75  to the heat sink  71  is provided by cutout  76 . The components  75  must be held in thermal contact with the heat sink  71  for operation. The components  75  may be bolted to the heat sink  71 ; however, this may not be necessary as the components  75  will be held in place by solder at the printed circuit board  70 . A thermally conductive paste may be used between the components  75  and the heat sink  71 . 
     The heat sink  71  and printed circuit board  70  are mounted to one another using bolts or other securing members  77 . A standoff  79  may be provided between the heat sink  71  and the printed circuit board  70  to allow for air flow between the heat sink  71  and the printed circuit board  70 . The standoff  79  may be in the form of a sleeve about the securing member  77 . 
     The control module  8  may be mounted in a variety of ways. For example, the control module  8  may be affixed to mounting plate  81  that forms an upper portion of the suction section  7  and a lower portion of the motor section  5 . A mounting flange  83  may be provided on the heat sink  71  for this purpose. Bolts or other securing members  85  may be used to secure the flange  83  to the mounting plate  81 . 
     The control module  8  may also be mounted by a strap  87  about the motor section  5 . One or more standoffs, not shown, may be required in order to provide proper spacing to allow cooling air to flow from the motor section  5  across the heat sink  71 . The strap  87  may be a continuous piece of material that extends around the motor section  5  and the heat sink  71 . The strap  87  may be a continuous piece of material that is attached to the heat sink  71  on opposite sides of the motor section  5  and extends about the motor section  5 . The strap  87  may also be made up of a series of straight pieces of material that are attached to one another to extend around the motor section  5 . 
     Other possible ways of mounting the control module  8  will be evident to those skilled in the art based on the principles described herein. 
     The control module  8  may be shaped to fit around protrusions from the motor section  5 . 
     Referring to  FIG. 5 , in a central vacuum unit  91  the apparatus  1  may be secured at the mounting plate  81  to a mounting bracket  92  that divides a motor chamber  93  from a suction chamber  94 . The motor section  5 , cooling section  3  and control module  8  are in the motor chamber  93 , while the suction section  7  is in the suction chamber  94 . An aperture  95  is provided in the motor chamber  93  to allow ambient air to be drawn into the cooling section from outside the central vacuum unit  91  a portion of the apparatus  1  may protrude through the aperture  95 . A shield  97  is usually mounted to the central vacuum unit  91  a distance above the apparatus  1  to ensure that cooling air is not inadvertently blocked by placing an object on the top of the central vacuum unit. Vents  98  are provided in the side of the motor chamber to allow cooling air to be exhausted from the unit. Vacuum air is exhausted from the unit  91  through piping  98 A. The control module  8  fits between the mounting plate and the top of the motor chamber  93 . Cooling air flows over and around the control module  8 . 
     As will be evident to those skilled in the art, apparatus  1  may be mounted within the unit  91  in many alternative ways. For example, a portion of the apparatus  1  may protrude through the aperture  95 . Also, the entire apparatus  1  may be within the motor chamber  93  with only an aperture, not shown, connecting the apparatus  1  to the suction chamber  94 . 
     The control module  8  is placed in the cooling air path after the motor section  5  and does not adversely affect the cooling of the motor section  5 . 
     Referring again to  FIGS. 1 and 2 , as shown, an optional filter module  99  may be mounted to the apparatus  1  in a manner similar to the control module  8 . For example, as shown in the FIGS., the filter module  99  may be mounted on an opposing side of the motor section  5  from the control module  8 . The strap  87  may be in two pieces joining the filter module  99  and the control module  8 . This is most easily done by bolting the straps  87  into heat sink  71  and a heat sink  100  of the filter module  99 . The straps  87  can be set such that they provide a press fit on the stator laminations. Many stator laminations used in vacuum cleaner motors have four opposing external sides. Other mounting methods will be evident to those skilled in the art based on the principles described herein. 
     The filter module  99  filters out electromagnetic interference (EMI) that may otherwise enter power lines  101  ( FIG. 6 ) connected to the apparatus  1 . As the filter module  99  and control module  8  are mounted to the apparatus  1 , all related connecting wire may be minimized. This reduces the radiating antenna effect of the wires. This in turn reduces secondary induced EMI between the wires and the power lines  101 . 
     Referring to  FIG. 7 , the central vacuum unit  91  is used to form part of a central vacuum system  102  utilizing piping  103 , wall valves  104 , hose  105 , handle  106 , wand  107 , and attachments  108  in a similar manner to existing central vacuum cleaning systems uses existing suction devices. 
     Referring to  FIG. 6 , an example block diagram of a control circuit  110  for a central vacuum cleaning system  102  is shown. The control circuit  110  has a controller  112  and switch  114  for controlling line power  116  to motor section  5 . The controller  112  and switch  114  form the control module  8  and are usually provided on a single printed circuit board  70 . The switch  114  may, for example, be a relay or a triac, not shown. 
     The control module  8  typically includes an AC-DC power supply  118  for powering the controller  112  and other components. Optional environmental conditions sensors  120  may be included in the control module  8  or as inputs to the control module  8 . The control module  8  may include indicators  122  for communication with a user. The indicators  122  may be remote from the control module  8 . 
     The environmental condition sensors  120  sense information about the environment in which the control module  8  is located. Such sensors  120  may include, for example, a temperature sensor  120   a  or a vibration sensor  120   b . Increased temperatures in the central vacuum unit  91  may indicate a problem with the apparatus  1 , such as worn brushes in the motor. Similarly, vibrations may indicate a problem with the apparatus  1 , such as worn bearings. 
     The physical location of the control module  8  in the cooling air path after the motor section  5  can provide an accurate measure of the temperature in the motor section  5 . Mounting the control module  8  to the apparatus  1  can provide an accurate indication of vibration at the apparatus  1 . The control module  8  can utilize inputs from a sensor  120  in any way desirable, for example, an alarm could be provided or power to the motor section  5  could be shut down. 
     The alarm or other communication may be transmitted from the control module  8  through wires or wirelessly for display through incorporating a display device, such as LCD display  122   a  or an LED array  122   b  or audible sounding through a sounder  122   c , for example a speaker or a piezoelectric buzzer. Example communication configurations are described in the inventor&#39;s U.S. patent application Ser. No. 10/936,699 filed 9 Sep. 2004 and International Patent Application number PCT/CA2005/000715 filed 11 May 2005 under title Central Vacuum Cleaning System Control Subsystems the content of which are hereby incorporated by reference into this description. 
     It will be understood by those skilled in the art that this description is made with reference to the preferred embodiment and that it is possible to make other embodiments employing the principles of the invention which fall within its spirit and scope as defined by the following claims.