CA1081409A - Constant performance vacuum cleaner - Google Patents
Constant performance vacuum cleanerInfo
- Publication number
- CA1081409A CA1081409A CA275,908A CA275908A CA1081409A CA 1081409 A CA1081409 A CA 1081409A CA 275908 A CA275908 A CA 275908A CA 1081409 A CA1081409 A CA 1081409A
- Authority
- CA
- Canada
- Prior art keywords
- motor
- air
- housing
- diaphragm
- outlet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Nozzles For Electric Vacuum Cleaners (AREA)
- Electric Vacuum Cleaner (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In accordance with the present invention, there is provided control means in a vacuum cleaner for automatically maintaining a substantially constant volumetric air flow with-in the limits of the capabilities of the system, under varying conditions of resistance to flow occurring any place in the line of flow from the suction nozzle to the inlet to the fan.
A further feature is the provision, as part of the control means, of an electric circuit which may be employed also to start and stop, by means of a switch on the hose handle, both the main fan motor and a motor for driving a brush in the nozzle.
In accordance with the present invention, there is provided control means in a vacuum cleaner for automatically maintaining a substantially constant volumetric air flow with-in the limits of the capabilities of the system, under varying conditions of resistance to flow occurring any place in the line of flow from the suction nozzle to the inlet to the fan.
A further feature is the provision, as part of the control means, of an electric circuit which may be employed also to start and stop, by means of a switch on the hose handle, both the main fan motor and a motor for driving a brush in the nozzle.
Description
Heretofore, various arrangements have been proposed for automatically changing the speed of a two-speed fan motor in a vacuum cleaner in response to certain varying conditions, but none has provided an automatic control which results in a ~ubstantially constant air flow under all conditions within, of course, the limits of the capabilities of the syste~. Thus, in U.S. Patent No. 2,789,660 of April 23, 1952, there is disclosed an arrangement whereby the speed of a two-speed fan motor is increased in a single step in response to a predetermined in-crease in pressure drop of air through the dust bag, but thecontrol in this patent is not responsive to change in air flow conditions at other points in the system, such as at the nozzle.
In U.S. Patent No. 3,069,068 of December 18, 1962, there is disclosed a vacuum cleaner having a two-speed fan motor, the speed of which is increased in a ~ingle step in response to a predetermined increase in pressure difference across the fan.
In neither of these patents is the system described capable of maintaining a substantially constant air flow by utilizing a pressure variation within the vacuum cleaner system and atmospheric pressure.
A construction in accordance with the present invent-ion includes a vacuum cleaner having a housing with an intake opening and an exhaust opening to atmosphere. A dust filter is provided within the housing between the openings. Means for introducing dust-ladened air into the housing through the intake opening is provided on one side of the filter and air moving means are provided within the housing having`an inlet communicat-ing with the other side of the filter and an outlet communicating with the exhaust opening. A motor is provided for driving the air-moving means. A fixed orifice is disposed across the path of airflow in the housing between the outlet and the exhaust opening to atmosphere. Means are also provided which are t~ '&~
i~ -1 ~ .
:
responsive to variations in air pressure occurring in the path of airflow between the outlet and the orifice for varying the sF~!ed of the motor in a manner to maintain substantially con-stant the volume of air per unit of time flowing through the housing.
The invention will now be described with reference to the accompanyina drawings which show a preferred form thereof and wherein:
Fig. 1 is a schematic view of a vacuum cleaner system embodying my invention.
Fig. 2 is a wiring diagram of a suitable electric cir-cuit for automatically controlling the fan motor shown in Fig. 1.
' .
.' ~ ' .
-la-10814()9 Fig 3 is a wiring diagram of a suitable electric cir-cuit for automatically controlling the fan motor of Fig. 1 and for manually starting and stopping said fan motor and a nozzle motor by means of a switch located on the vacuum cleaner hose.
Fig. 4 is a graph of static pressure at the end of the hose measured in height of water lift plotted against air flow measured in quantity of air per unit of time, the curves showing vacuum cleaner performances.
Referring to the drawings and particularly to Fig 1, reference character 10 designates a vacuum cleaner housing at one end of which is a removable cover 11 to which is removably connected a hose 12 leading from a hollow handle 13 of a suction nozzle 14. This nozzle includes a rotary brush 16 driven by an electric motor 18 which, in well known manner, is supplied with power through conductors (not shown) built into hose 12 and the handle or wand 13.
Within housing 10 adjacent to cover 11 is a removable filter bag made of a material permeable with respect to air which serves to filter out and collect dust carried by air entering the bag through hose 12. Also within the housing and adjacent to bag 20 is a centrifugal fan 22 driven by an electric motor 24 The outlet 26 of the fan is connected to the interior of the housing of motor 24 so that all of the air passes through the motor for cooling the armature and field, and is discharged through openings 28 in the motor housing to the interior of housing 10 adjacent to an outlet opening 30 through which the air is discharged to atmosphere. The air passages through motor 24 constitute a substantially fixed orifice for throttling air between the outlet 26 of the fan and atmosphere.
A tube 32 leads from the interior of the motor housing at a point adjacent to outlet 26 and ahead of the fixed orifice to a diaphragm chamber 34 of a pressure transducer 36. One side .... . ~, . . . . . . . . .
-- 10814()9 of chamber 34 is closed by a diaphragm 38, the other exterior side of which is subject to atmospheric pressure. Bearing aga:inst the outer side of the diaphragm 38 is a post 40 mounted on lhe end of an arm 42 pivoted at 44 to a fixed arm 46 A
spring 47 urges arm 42 in a direction causing post 40 to bear against the diaphragm 38: Mounted on post 40 is a shutter 48 having an aperture 50. A light source 52 is disposed on one side of the shutter, and a photoresistor cell 54 is located on the other so that more or less light from source 56 may pass through aperture 50 to cell 54 depending on the position of shutter 48 as determined by diaphragm 38 In Fig, 2 there is shown a suitable electric circuit for varying the speed of fan motor 24 in accordance with pres-sure variations of air measured between the outlet 26 of fan 22 and the constant orifice provided by the air passages through the motor. As here shown, the fan motor 24 is supplied with current from the 120 volt alternating current line 60 through a manual on-off switch 62 and a triac 64. As is well known, the triac controls the flow of current therethrough by interupt-ing flow during a portion of each cycle of the alternating cur-rent, the extent of the portion being controlled by an impulse from a gate circuit 68, including a diac 70, a capacitor 72 and the photoresistor cell 54, The resistance of cell 54 is decreased by an increase in the illumination reaching it from the light source 52 through the aperture 50 of shutter 48 and a decrease in resistance causes ` the gate circuit to decrease the portion of the cycle which is `` interrupted by triac 64, thus increasing the speed of motor 34.
~ Shutter 48 is so arranged with respect to light soùrce 52 and : 30 cell 54 that when diaphragm 38 is at rest, that is, subjected to atmospheric pressure on both sides and the force of spring 47, the aperture 50 is positioned to permit maximum illumination , . : . :
.. . . ..
- 1081~(~9 of cell 54, while downward or upward a displacement of the dia-phragm causes the shutter to reduce the illumination reaching the cell 54.
The above device operates as follows: Assume that the filter bag 20 is clean and hence offers minimum resistance to flow of air therethrough and that the nozzle 14 is on a rug or carpet having an open weave which offers low resistance to flow of air into the nozzle and that switch 62 is closed. Under these conditions of low resistance to flow through the system, the fan 22 has a large volume of air available to move and hence discharges a large volume through outlet 26 into the motor hous-ing, Becaus~ of the fixed orifice provided by the passages through motor 24, this causes a relatively high pressure to exist at outlet 26, which is communicated through tube 37 to dia-phragm chamber 34 and displaces the diaphragm 38 upwardly against atmospheric force acting on the outer side of the diaphragm and the for of spring 47. This in turn moves shutter 48 upwardly so as to decrease the illumination of cell 54, which increases the resistance of the cell 54 so as to cause triac 64 to decrease the motor speed, which is desired as a slower fan speed is suf-ficient to move the desired constant volume of air through the system because of low resistance to flow into the nozzle and through the filter bag.
If the resistance to flow of air into the nozzle is increased, as by placing the nozzle on a carpet of tighter weave, the volume of air moved by fan 22 is decreased and the pressure transmitted by tube 32 is decreased. This causes diaphragm 38 to move downwardly to in turn increase the illumination of cell 54, which increases motor speed, which is desirable in order to maintain constant air flow in spite of the increased resistance of flow into the nozzle.
~ As filter bag 20 fills with dirt and becomes more ~08140~
clogged, the resistance to the flow of air therethrough increases, and this has the same effect as increasing the resistance to flow into the nozzle as described above. Thus, motor 24 is speeded up to enable the fan 22 to maintain a constant ~low of air as the filter bag fills or becomes clogged with dust.
Thus, the motor speed is automatically controlled in a manner causing the fan to maintain a substantially constant vol-umetric flow of air through the system under variations in the resistance to flow of air occurring at any point between the nozzle and the fan. Of course, should the nozzle inlet be com-pletely sealed so that no air may enter, it is impossible for the fan, no matter what its capacity is, to move any air through the system, but the fan would be rotating at its greatest speed.
Fig, 4 is a graph showing negative air pressure (vacuum) in the system at the suction side of the fan, measured, for in-stance, in inches of water lift, plotted against the volume of air flow. Curve 1 is for a typical vacuum cleaner without con-trols. Thus, at sealed suction, the vacuum is the maximum which the fan is capable of producing and the quantity of air flowing is zero. If the resistance to air flow through the system is reduced, the vacuum falls and the quantity of air increaqes until, at the lower end of curve 1, the quantity of air is the maximum which the fan is capable of moving, and the vacuum (water-lift) is very low, Upper curve 2, 2a shows the performance of the motor-fan unit of the vacuum cleaner in accordance with the present invention if operated without controls, that is, with the motor 24 operating at full speed at all times. It will be seen that it is similar to curve 1, except that the performance is higher at all times, which is higher than desirable under certain con-ditions, as will appear below.
Lower curve 3, 3a shows the performance of the motor 11~81409 fan unit 22-24 if the motor is operated at all times at the minimum speed obtainable by the controls in accordance with the preqlent invention. It likewise is similar to curve 1, except that the performance is lower at all times, which is lower than desirable under certain other conditions.
The solid line curve, made up of curves 2, 3a and a very steep connecting curve 4, represents the performance of the vacuum cleaner in accordance with the present invention, curve 4 showing the relationship between vacuum (water-lift) and air flow within the limits, represented by the vertical broken lines 5 and 6, of the capabilities of the system, Within these limits (between lines 5 and 6) it will be seen that there is very little variation in air flow over a relatively large change in vacuum, and this variation in air flow (distance between lines 5 and 6) depends on the sensitivity of pressure transducer 36. Obviously, some change in pressure of the air acting on diaphragm 38 is necessary in order to cause movement thereof.
The horizontal location of the lines 5 and 6 in Fig. 4, i.e., air flow value, may be changed by changing the characteri-stics of the control system, such as by altering the force ex-erted by spring 47 by changing the setting of a set-screw 74 against which the spring bears Decreasing the force of this spring moves the lines 5 and 6 to the left, and increasing the force moves the lines to the right.
Should the resistance to air flow be increased so as to reduce the air flow below the value represented by the upper end of curve 4, the relationship between vacuum and air flow follows the curve 2 until maximum vacuum is attained at sealed suction, that is, zero air flow~ Likewise, if resistance to air flow is greatly reduced, as by removing cover 11 and filter bag 20, thus increasing the flow beyond the value represented by the lower end of curve 4, the relationship between vacuum and air ~ . . - .
, : . - : -: . : .: ,, flow follows the curve 3a until maximum air flow is reached.
With a vacuum cleaner as shown in Fig. 1, it is desir-able for the operator to be able to start and stop the fan motor 24 by means of a switch located near the end of hose 12 where the latter is connected to handle 13 of nozzle 14, and the cir-cuit shown in Fig, 2 may-be adapted to this purpose in the man-ner illustrated in Fig. 3, In Fig,3 the elements common to Fig, 2 :
are designated by the same reference characters, The conductors in hose 12 which supply current to nozzle motor 18 are numbered 76 and 78 and are connected through separable contacts 80 and 82, respectively, with the 120 v, line 60 in the cleaner housing 10, A single pole, double-throw switch 84 is provided in conductor 78 and is located on hose 12 near its juncture with handle 13 of the nozzle, In the position of switch 84 as shown in Fig,3, the eireuit is eompleted to motor 18, and if main switch 62 is elosed, eurrent is supplied direetly to motor 18, and to fan motor 24 through the control eircuit including triac 64, as explained in connection with Fig, 2, In addition to the power conductors 76 and 78, there is a small gauge control conductor 86 which is connected to pole 88 of switch 84 and through a separable contact 90 with the conductor leading from capacitor 72 to diac 70, When switch 84 is thrown to close the circuit through pole 88, it interrupts the supply of current to nozzle motor 18 and closes a shunt circuit around capacitor 72, This -renders gate eircuit 68 inoperative to trigger triac 64, and henee no eurrent is transmitted therethrough to fan motor 24, The wiring diagram of Fig, 3 also ineludes a single pole double-throw switeh 92 whieh is operated in well-known manner (see U,S, Patent No, 2,814,358 of November 26, 1957) in response to pressure drop through filter bag 20 to automatieally throw the switeh from the position shown when this pressure drops, whieh is an indieation of the elogging of the bag, reaehes . . :
iO81409 a value such that the bag should be removed and replaced by a clean one Throwing of the switch 92 opens the control for the gate circuit, and hence triac 64 is not triggered and does not permit the passage of current therethr~ugh to motor 24 At the same time switch 92 completes a circuit across line 60 through motor 24, a signal lamp 94 and a high resistance 96, The latter limits the flow of current through this circuit to a value below that required to operate motor 24 but sufficient to light lamp 94, thus indicating to the operator that motor 24 has stopped because of a dirty filter bag, and not because of an extraneous loss of power caused, for instance, by a blown fuse or circuit breaker in the house circuit or by an inadvertent removal of a plug from a wall outlet.
If the vacuum cleaner is operated without the hose 12 being connected to front cover 11, as is the case when the cleaner is used for blowing by connecting the hose to outlet 30, the cir-cuits are opened at the separable contacts 80, 82 and 90. Under these conditions the circuit in the cleaner for controlling the speed of motor 24 will operate as above described, but, of course, the operator cannot stop motor 24 by manipulating switch 84, but only by opening main switch 62, When the cleaner is used for blowing, the air flow to the fan inlet encounters a minimum re-striction. The control then would act to reduce the air flow to the curve 3a for minimum motor speed performance. To provide maximum performance for blowing operation, a single-pole double-throw switch 97 is mechanically activated when the hose is con-nected to the exhaust opening 30 to connect the motor directly through a conductor 98 to switch 62, thus bypassing the motor control and providing full power to the motor. When the hose is disconnected from the exhaust opening, the switch 97 is returned to nQrmal position and the motor is controlled as described pre-viously.
It will thus be seen that I have provided a system which, within the limits of its capabilities, automatically main.tains a substantially constant flow of air through a vacuum clea.ner regardless of wide variations in the resistance to air flow occurring at any point in the cleaner on the suction side of the blower.
_g_ : - '
In U.S. Patent No. 3,069,068 of December 18, 1962, there is disclosed a vacuum cleaner having a two-speed fan motor, the speed of which is increased in a ~ingle step in response to a predetermined increase in pressure difference across the fan.
In neither of these patents is the system described capable of maintaining a substantially constant air flow by utilizing a pressure variation within the vacuum cleaner system and atmospheric pressure.
A construction in accordance with the present invent-ion includes a vacuum cleaner having a housing with an intake opening and an exhaust opening to atmosphere. A dust filter is provided within the housing between the openings. Means for introducing dust-ladened air into the housing through the intake opening is provided on one side of the filter and air moving means are provided within the housing having`an inlet communicat-ing with the other side of the filter and an outlet communicating with the exhaust opening. A motor is provided for driving the air-moving means. A fixed orifice is disposed across the path of airflow in the housing between the outlet and the exhaust opening to atmosphere. Means are also provided which are t~ '&~
i~ -1 ~ .
:
responsive to variations in air pressure occurring in the path of airflow between the outlet and the orifice for varying the sF~!ed of the motor in a manner to maintain substantially con-stant the volume of air per unit of time flowing through the housing.
The invention will now be described with reference to the accompanyina drawings which show a preferred form thereof and wherein:
Fig. 1 is a schematic view of a vacuum cleaner system embodying my invention.
Fig. 2 is a wiring diagram of a suitable electric cir-cuit for automatically controlling the fan motor shown in Fig. 1.
' .
.' ~ ' .
-la-10814()9 Fig 3 is a wiring diagram of a suitable electric cir-cuit for automatically controlling the fan motor of Fig. 1 and for manually starting and stopping said fan motor and a nozzle motor by means of a switch located on the vacuum cleaner hose.
Fig. 4 is a graph of static pressure at the end of the hose measured in height of water lift plotted against air flow measured in quantity of air per unit of time, the curves showing vacuum cleaner performances.
Referring to the drawings and particularly to Fig 1, reference character 10 designates a vacuum cleaner housing at one end of which is a removable cover 11 to which is removably connected a hose 12 leading from a hollow handle 13 of a suction nozzle 14. This nozzle includes a rotary brush 16 driven by an electric motor 18 which, in well known manner, is supplied with power through conductors (not shown) built into hose 12 and the handle or wand 13.
Within housing 10 adjacent to cover 11 is a removable filter bag made of a material permeable with respect to air which serves to filter out and collect dust carried by air entering the bag through hose 12. Also within the housing and adjacent to bag 20 is a centrifugal fan 22 driven by an electric motor 24 The outlet 26 of the fan is connected to the interior of the housing of motor 24 so that all of the air passes through the motor for cooling the armature and field, and is discharged through openings 28 in the motor housing to the interior of housing 10 adjacent to an outlet opening 30 through which the air is discharged to atmosphere. The air passages through motor 24 constitute a substantially fixed orifice for throttling air between the outlet 26 of the fan and atmosphere.
A tube 32 leads from the interior of the motor housing at a point adjacent to outlet 26 and ahead of the fixed orifice to a diaphragm chamber 34 of a pressure transducer 36. One side .... . ~, . . . . . . . . .
-- 10814()9 of chamber 34 is closed by a diaphragm 38, the other exterior side of which is subject to atmospheric pressure. Bearing aga:inst the outer side of the diaphragm 38 is a post 40 mounted on lhe end of an arm 42 pivoted at 44 to a fixed arm 46 A
spring 47 urges arm 42 in a direction causing post 40 to bear against the diaphragm 38: Mounted on post 40 is a shutter 48 having an aperture 50. A light source 52 is disposed on one side of the shutter, and a photoresistor cell 54 is located on the other so that more or less light from source 56 may pass through aperture 50 to cell 54 depending on the position of shutter 48 as determined by diaphragm 38 In Fig, 2 there is shown a suitable electric circuit for varying the speed of fan motor 24 in accordance with pres-sure variations of air measured between the outlet 26 of fan 22 and the constant orifice provided by the air passages through the motor. As here shown, the fan motor 24 is supplied with current from the 120 volt alternating current line 60 through a manual on-off switch 62 and a triac 64. As is well known, the triac controls the flow of current therethrough by interupt-ing flow during a portion of each cycle of the alternating cur-rent, the extent of the portion being controlled by an impulse from a gate circuit 68, including a diac 70, a capacitor 72 and the photoresistor cell 54, The resistance of cell 54 is decreased by an increase in the illumination reaching it from the light source 52 through the aperture 50 of shutter 48 and a decrease in resistance causes ` the gate circuit to decrease the portion of the cycle which is `` interrupted by triac 64, thus increasing the speed of motor 34.
~ Shutter 48 is so arranged with respect to light soùrce 52 and : 30 cell 54 that when diaphragm 38 is at rest, that is, subjected to atmospheric pressure on both sides and the force of spring 47, the aperture 50 is positioned to permit maximum illumination , . : . :
.. . . ..
- 1081~(~9 of cell 54, while downward or upward a displacement of the dia-phragm causes the shutter to reduce the illumination reaching the cell 54.
The above device operates as follows: Assume that the filter bag 20 is clean and hence offers minimum resistance to flow of air therethrough and that the nozzle 14 is on a rug or carpet having an open weave which offers low resistance to flow of air into the nozzle and that switch 62 is closed. Under these conditions of low resistance to flow through the system, the fan 22 has a large volume of air available to move and hence discharges a large volume through outlet 26 into the motor hous-ing, Becaus~ of the fixed orifice provided by the passages through motor 24, this causes a relatively high pressure to exist at outlet 26, which is communicated through tube 37 to dia-phragm chamber 34 and displaces the diaphragm 38 upwardly against atmospheric force acting on the outer side of the diaphragm and the for of spring 47. This in turn moves shutter 48 upwardly so as to decrease the illumination of cell 54, which increases the resistance of the cell 54 so as to cause triac 64 to decrease the motor speed, which is desired as a slower fan speed is suf-ficient to move the desired constant volume of air through the system because of low resistance to flow into the nozzle and through the filter bag.
If the resistance to flow of air into the nozzle is increased, as by placing the nozzle on a carpet of tighter weave, the volume of air moved by fan 22 is decreased and the pressure transmitted by tube 32 is decreased. This causes diaphragm 38 to move downwardly to in turn increase the illumination of cell 54, which increases motor speed, which is desirable in order to maintain constant air flow in spite of the increased resistance of flow into the nozzle.
~ As filter bag 20 fills with dirt and becomes more ~08140~
clogged, the resistance to the flow of air therethrough increases, and this has the same effect as increasing the resistance to flow into the nozzle as described above. Thus, motor 24 is speeded up to enable the fan 22 to maintain a constant ~low of air as the filter bag fills or becomes clogged with dust.
Thus, the motor speed is automatically controlled in a manner causing the fan to maintain a substantially constant vol-umetric flow of air through the system under variations in the resistance to flow of air occurring at any point between the nozzle and the fan. Of course, should the nozzle inlet be com-pletely sealed so that no air may enter, it is impossible for the fan, no matter what its capacity is, to move any air through the system, but the fan would be rotating at its greatest speed.
Fig, 4 is a graph showing negative air pressure (vacuum) in the system at the suction side of the fan, measured, for in-stance, in inches of water lift, plotted against the volume of air flow. Curve 1 is for a typical vacuum cleaner without con-trols. Thus, at sealed suction, the vacuum is the maximum which the fan is capable of producing and the quantity of air flowing is zero. If the resistance to air flow through the system is reduced, the vacuum falls and the quantity of air increaqes until, at the lower end of curve 1, the quantity of air is the maximum which the fan is capable of moving, and the vacuum (water-lift) is very low, Upper curve 2, 2a shows the performance of the motor-fan unit of the vacuum cleaner in accordance with the present invention if operated without controls, that is, with the motor 24 operating at full speed at all times. It will be seen that it is similar to curve 1, except that the performance is higher at all times, which is higher than desirable under certain con-ditions, as will appear below.
Lower curve 3, 3a shows the performance of the motor 11~81409 fan unit 22-24 if the motor is operated at all times at the minimum speed obtainable by the controls in accordance with the preqlent invention. It likewise is similar to curve 1, except that the performance is lower at all times, which is lower than desirable under certain other conditions.
The solid line curve, made up of curves 2, 3a and a very steep connecting curve 4, represents the performance of the vacuum cleaner in accordance with the present invention, curve 4 showing the relationship between vacuum (water-lift) and air flow within the limits, represented by the vertical broken lines 5 and 6, of the capabilities of the system, Within these limits (between lines 5 and 6) it will be seen that there is very little variation in air flow over a relatively large change in vacuum, and this variation in air flow (distance between lines 5 and 6) depends on the sensitivity of pressure transducer 36. Obviously, some change in pressure of the air acting on diaphragm 38 is necessary in order to cause movement thereof.
The horizontal location of the lines 5 and 6 in Fig. 4, i.e., air flow value, may be changed by changing the characteri-stics of the control system, such as by altering the force ex-erted by spring 47 by changing the setting of a set-screw 74 against which the spring bears Decreasing the force of this spring moves the lines 5 and 6 to the left, and increasing the force moves the lines to the right.
Should the resistance to air flow be increased so as to reduce the air flow below the value represented by the upper end of curve 4, the relationship between vacuum and air flow follows the curve 2 until maximum vacuum is attained at sealed suction, that is, zero air flow~ Likewise, if resistance to air flow is greatly reduced, as by removing cover 11 and filter bag 20, thus increasing the flow beyond the value represented by the lower end of curve 4, the relationship between vacuum and air ~ . . - .
, : . - : -: . : .: ,, flow follows the curve 3a until maximum air flow is reached.
With a vacuum cleaner as shown in Fig. 1, it is desir-able for the operator to be able to start and stop the fan motor 24 by means of a switch located near the end of hose 12 where the latter is connected to handle 13 of nozzle 14, and the cir-cuit shown in Fig, 2 may-be adapted to this purpose in the man-ner illustrated in Fig. 3, In Fig,3 the elements common to Fig, 2 :
are designated by the same reference characters, The conductors in hose 12 which supply current to nozzle motor 18 are numbered 76 and 78 and are connected through separable contacts 80 and 82, respectively, with the 120 v, line 60 in the cleaner housing 10, A single pole, double-throw switch 84 is provided in conductor 78 and is located on hose 12 near its juncture with handle 13 of the nozzle, In the position of switch 84 as shown in Fig,3, the eireuit is eompleted to motor 18, and if main switch 62 is elosed, eurrent is supplied direetly to motor 18, and to fan motor 24 through the control eircuit including triac 64, as explained in connection with Fig, 2, In addition to the power conductors 76 and 78, there is a small gauge control conductor 86 which is connected to pole 88 of switch 84 and through a separable contact 90 with the conductor leading from capacitor 72 to diac 70, When switch 84 is thrown to close the circuit through pole 88, it interrupts the supply of current to nozzle motor 18 and closes a shunt circuit around capacitor 72, This -renders gate eircuit 68 inoperative to trigger triac 64, and henee no eurrent is transmitted therethrough to fan motor 24, The wiring diagram of Fig, 3 also ineludes a single pole double-throw switeh 92 whieh is operated in well-known manner (see U,S, Patent No, 2,814,358 of November 26, 1957) in response to pressure drop through filter bag 20 to automatieally throw the switeh from the position shown when this pressure drops, whieh is an indieation of the elogging of the bag, reaehes . . :
iO81409 a value such that the bag should be removed and replaced by a clean one Throwing of the switch 92 opens the control for the gate circuit, and hence triac 64 is not triggered and does not permit the passage of current therethr~ugh to motor 24 At the same time switch 92 completes a circuit across line 60 through motor 24, a signal lamp 94 and a high resistance 96, The latter limits the flow of current through this circuit to a value below that required to operate motor 24 but sufficient to light lamp 94, thus indicating to the operator that motor 24 has stopped because of a dirty filter bag, and not because of an extraneous loss of power caused, for instance, by a blown fuse or circuit breaker in the house circuit or by an inadvertent removal of a plug from a wall outlet.
If the vacuum cleaner is operated without the hose 12 being connected to front cover 11, as is the case when the cleaner is used for blowing by connecting the hose to outlet 30, the cir-cuits are opened at the separable contacts 80, 82 and 90. Under these conditions the circuit in the cleaner for controlling the speed of motor 24 will operate as above described, but, of course, the operator cannot stop motor 24 by manipulating switch 84, but only by opening main switch 62, When the cleaner is used for blowing, the air flow to the fan inlet encounters a minimum re-striction. The control then would act to reduce the air flow to the curve 3a for minimum motor speed performance. To provide maximum performance for blowing operation, a single-pole double-throw switch 97 is mechanically activated when the hose is con-nected to the exhaust opening 30 to connect the motor directly through a conductor 98 to switch 62, thus bypassing the motor control and providing full power to the motor. When the hose is disconnected from the exhaust opening, the switch 97 is returned to nQrmal position and the motor is controlled as described pre-viously.
It will thus be seen that I have provided a system which, within the limits of its capabilities, automatically main.tains a substantially constant flow of air through a vacuum clea.ner regardless of wide variations in the resistance to air flow occurring at any point in the cleaner on the suction side of the blower.
_g_ : - '
Claims (9)
1. In a vacuum cleaner, a housing having an intake opening and an exhaust opening to atmosphere, a dust filter within said housing between said openings, means for introducing dust-ladened air into said housing through said intake opening to one side of said filter, air moving means within said housing having an inlet communicating with the other side of said filter and an outlet communicating with said exhaust opening, a motor for driving said air-moving means, a fixed orifice disposed across the path of airflow in said housing between said outlet and said exhaust opening to atmosphere, and means responsive to variations in air pressure occurring in the path of airflow between said outlet and said orifice for varying the speed of said motor in a manner to maintain substantially constant the volume of air per unit of time flowing through said housing.
2. The combination as set forth in claim 1 in which said motor is an electric motor having a housing connected to receive the air discharged through said outlet, and said fixed orifice has passages provided through said motor.
3. The combination as set forth in claim 1, in which said motor is an electric motor, and said means responsive to variations in air pressure includes a triac in the circuit of said motor, a triggering circuit for said triac including a diac and a variable electric resistance, and means including a diaphragm acted on by said variations in air pressure for varying said resistance.
4. The combination as set forth in claim 3 in which said variable resistance is a photoresistor cell, and in-cluding a source of illumination and a shutter movable by said diaphragm for varying the amount of illumination re-ceived by said cell from said source.
5. The combination as set forth in claim 4 in which the first mentioned means is a hose removably connected to said housing and including a suction nozzle connected to said hose, an electric motor in said nozzle, a pair of electric conductors in said hose for supplying current to the last mentioned motor, a switch on said hose in one of said conductors having one position for interrupting said con-ductor and completing a circuit through a third conductor in said hose for shunting a portion of said triggering circuit to render the latter inoperative.
6. The combination as set forth in claim 3, including a switch for bypassing said triac to cause said motor to run at full speed.
7. In a vacuum cleaner system, a suction nozzle, a conduit connected at one end to said nozzle, a hollow body connected to the other end of said conduit, a suction fan in said body having an inlet and an outlet, a dust filter in said body in the line of flow between said conduit and said inlet, an electric motor for driving said fan, said motor having air passage therethrough constituting a fixed orifice, means for directing all of the air discharged from said out-let to pass through said orifice, a diaphragm subjected on one side to atmospheric pressure, means for subjecting the other side of said diaphragm to the air pressure existing in said hollow body between said outlet and said orifice, and means responsive to movement of said diaphragm caused by a decrease in said pressure for increasing the speed of said motor to maintain substantially constant airflow through said nozzle.
8. A vacuum cleaner system as defined in claim 7, in which the last-mentioned means includes a triac in the cir-cuit of said motor for varying the speed of the latter, a triggering circuit for said triac including a diac and a variable resistance, and means for varying said resistance in response to movement of said diaphragm.
9. A vacuum cleaner system as defined in claim 8 in which said variable resistance is a photoresistor cell, and including a source of illumination and an apertured shutter movable by said diaphragm for varying the amount of illumi-nation received by said cell from said source in accordance with variations in said pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA275,908A CA1081409A (en) | 1977-04-07 | 1977-04-07 | Constant performance vacuum cleaner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA275,908A CA1081409A (en) | 1977-04-07 | 1977-04-07 | Constant performance vacuum cleaner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1081409A true CA1081409A (en) | 1980-07-15 |
Family
ID=4108359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA275,908A Expired CA1081409A (en) | 1977-04-07 | 1977-04-07 | Constant performance vacuum cleaner |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1081409A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107552422A (en) * | 2017-09-13 | 2018-01-09 | 国家电网公司 | Fence automatic impurity-removing thing device |
-
1977
- 1977-04-07 CA CA275,908A patent/CA1081409A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107552422A (en) * | 2017-09-13 | 2018-01-09 | 国家电网公司 | Fence automatic impurity-removing thing device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4021879A (en) | Constant performance vacuum cleaner | |
| US4399585A (en) | Vacuum cleaner with constant air flow | |
| US3180071A (en) | Suction cleaner | |
| US4733430A (en) | Vacuum cleaner with operating condition indicator system | |
| US4294595A (en) | Vacuum cleaner including automatic shutoff device | |
| EP0778066B1 (en) | Filter condition sensor and indicator system | |
| US5613269A (en) | Recirculating type cleaner | |
| US4370776A (en) | Vacuum cleaner for household and industrial application | |
| US4841595A (en) | Vacuum pump-out system for wet/dry vacuum cleaner | |
| US6768073B1 (en) | Pivoting handle and control arrangement for a floor care appliance | |
| US4121199A (en) | Sentinel system for grease extracting ventilators | |
| US2443162A (en) | Vacuum cleaner | |
| JPH0838408A (en) | Electronic vacuum cleaner control system | |
| WO2000059357A1 (en) | Vacuum cleaner | |
| US5201095A (en) | Motor controlling apparatus for a vacuum cleaner | |
| CA2101484A1 (en) | Vacuum outlet for built in vacuum | |
| CA1081409A (en) | Constant performance vacuum cleaner | |
| US2534479A (en) | Handle actuated delayed motor disconnect for suction cleaners | |
| US4233706A (en) | Apparatus for cleaning of large scale textile coverings, especially carpets and wall to wall carpeting | |
| US2715946A (en) | Adjustable control for automatic vacuum cleaners | |
| CN101214132A (en) | Suction nozzle for vacuum cleaner | |
| US2715452A (en) | Suction cleaner | |
| US5433762A (en) | Filtered air moving apparatus | |
| US2406915A (en) | Suction cleaner | |
| JPH027705B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |