Patent Publication Number: US-2007107159-A1

Title: Suction device and nozzle device

Description:
BACKGROUND  
      The present invention relates to a suction device which comprises a nozzle for sucking in the outside air and is capable of expelling a fluid over an object, and this invention also relates to a nozzle device capable of sucking in the outside air and expelling a fluid over the object.  
      Conventionally, it is relatively difficult to remove and clean unwanted matter, such as dirt, adhering to objects (or cleaned objects) such as walls, ceilings, floors, bathroom surfaces, furniture, equipment such as ventilating fans or air conditioners, various kinds of manufacturing machines, and vehicles such as cars, motorcycles, or bicycles. Particularly, it is very difficult to wipe or wash off grease adhering to these cleaned objects with normal cleaning fluid.  
      Accordingly, a cleaning device that cleans dirt off with a spraying force of a cleaning fluid sprayed on the dirt adhering to the cleaned object has recently been suggested. Moreover, any unwanted matter that cannot be cleaned off by the cleaning device is removed by, for example, further scrubbing the dirt with a cloth, a scrubbing brush, a mop or the like. However, when this cleaning device is used to clean off the dirt adhering to horizontal surfaces such as floors, the cleaning fluid sprayed over the floors or other horizontal surfaces and the dirt removed by the cleaning fluid (the “sprayed cleaning fluid” and the “dirt removed by the cleaning fluid” may be collectively and simply referred to as “wastewater” below) remain on the floors or other horizontal surfaces. Accordingly, it is necessary to further wipe them with, for example, a cloth.  
      Moreover, when the dirt adheres to vertical surfaces such as walls, or ceilings or the like, the cleaning fluid sprayed over them and the dirt removed by the cleaning fluid run down or fall. Therefore, it is necessary to wipe the wastewater with, for example, a cloth. If the wastewater runs or falls onto any clean part of the vertical surfaces or ceilings, it is also necessary to clean this part. Furthermore, if plants, furniture, electric appliances or the like are placed beside the walls or under the ceilings to be cleaned, and if the cleaning fluid runs or drips onto them, the problems of killing the plants, or damaging the furniture or the failure of the electric appliances may result. Accordingly, in this case, when cleaning the dirt off the walls or ceilings, it is necessary to cover the plants, furniture, electric appliances or the like with, for example, a vinyl sheet so that the wastewater will not drip onto them directly.  
      As the number of elderly persons, who need care because they are bedridden or suffer from dementia, has been increasing sharply recently, the care of such persons, particularly the disposal of excrement, has become a very important issue. Diapers are generally used for the disposal of excrement of the elderly persons in the above-described conditions. Specifically speaking, the disposal of excrement is now conducted by changing diapers regularly or once they are soiled. However, just changing diapers will leave residual excrement on the body, giving rise to problems of sanitary management. Accordingly, it is still necessary to remove the residual excrement on the body when changing diapers.  
      Such a task has been conducted by using commercially available cleaning items or hot wet towels. Namely, the current way of removing the residual excrement is for a caregiver to directly wipe a feculent part of the body of an elderly person, that is, the residual excrement on the body. However, the residual excrement on the body often solidifies by the time of changing diapers and much time and labor is required for the removal of the excrement by hand.  
      Therefore, the applicant of this invention has suggested, in Japanese Patent Laid-Open (Kokai) Publication No. 2001-161762, a suction device capable of easily sucking in and removing the above-described matter, such as dirt.  
      Moreover, Japanese Patent Laid-Open (Kokai) Publications No. 2001-245952, No. 2001-245953, No. 2001-261968, No. 2001-276172, and No. 2001-299903 disclose various nozzle structures which are connected to the suction device as described above and are used to suck in the matter.  
      However, the above-mentioned nozzle structures disclosed in Japanese Patent Laid-Open (Kokai) Publications No. 2001-245952, No. 2001-245953, No. 2001-261968, No. 2001-276172, and No. 2001-299903 are characterized in that when the fluid is expelled out of the nozzle during the suction operation and even if the nozzle is moved away from a surface, to which the matter to be sucked is adhering, the fluid will not be scattered about. However, the nozzle structures are complicated in order to realize the above-described feature.  
     SUMMARY  
      The present invention aims to improve the above-described conventional suction devices and nozzle devices. It is the object of this invention to provide a suction device and a nozzle device, whose structures are simple, which can cause a fluid to be automatically expelled out of a nozzle toward an object by placing the nozzle close to or in contact with the object when conducting a suction operation, and which can automatically stop the fluid from ejecting out of the nozzle when the nozzle is moved away from the object.  
      In order to achieve the above-described object, this invention provides a suction device comprising a nozzle for sucking in the outside air, wherein the suction device is structured in such a manner that: a fluid nozzle is provided within the nozzle in order to expel a fluid toward the opening of the nozzle; when the opening of the nozzle is unobstructed, the outside air being sucked into the nozzle through its opening causes the fluid being expelled out of the fluid nozzle to be pushed back and sucked into the nozzle from its base end without the fluid being ejected out of the nozzle; and when the amount of the outside air sucked into the nozzle is decreased by placing the opening of the nozzle close to or in contact with an object, the fluid expelled out of the fluid nozzle overcomes the outside air and thereby the fluid is ejected toward the object, and the fluid that has struck the object is sucked in together with the outside air into the nozzle.  
      Merely by simple operation of moving the nozzle close to the object or causing the nozzle to contact the object, the suction device having the above-described structure can cause the fluid to be automatically expelled out of the nozzle and can also suck in the fluid that has struck the object. The suction device can also stop the fluid ejecting out of the nozzle merely by moving the nozzle away from the object.  
      It is possible to form, in the vicinity of the opening of the nozzle, at least one small hole capable of introducing the outside air into the nozzle.  
      By forming such a small hole, it is possible to introduce the outside air through the small hole into the nozzle even if a negative pressure is formed inside the nozzle by causing the nozzle to closely contact the object. Accordingly, it is possible to smoothly move the nozzle in relation to the object and to recover the wastewater smoothly.  
      The suction device of this invention can be structured in such a manner that a fluid injection hole of the fluid nozzle is located at a position recessed from the opening of the nozzle.  
      Concerning the suction device of this invention, either the amount of the outside air or the pressure of the fluid, or both of them, can be adjusted so that: when the opening of the nozzle is unobstructed, the pressure of the outside air corresponding to the amount of the outside air sucked into the nozzle exceeds the pressure of the fluid expelled out of the fluid nozzle in an area between the opening of the nozzle and the fluid injection hole; and when the amount of the outside air sucked into the nozzle is decreased, the pressure of the fluid expelled out of the fluid nozzle exceeds the pressure of the outside air that corresponds to the amount of the outside air sucked into the nozzle in the area between the opening of the nozzle and the fluid injection hole.  
      Moreover, regarding the suction device of this invention, the cross-section area of the opening of the nozzle can be determined based on the pressure of the fluid expelled out of the fluid nozzle, thereby controlling the amount of outside air sucked into the nozzle.  
      Concerning the suction device of this invention, the distance between the opening of the nozzle and the fluid injection hole can be determined based on the pressure of the outside air corresponding to the amount of outside air sucked into the nozzle, as well as the pressure of the fluid expelled out of the fluid nozzle.  
      Moreover, the suction device of this invention can be structured in such a manner that when the amount of outside air sucked into the nozzle is decreased, the fluid expelled out of the fluid injection nozzle is ejected toward the object and the matter to be sucked, which is adhering to the object, so that the matter, together with the outside air and the fluid that has struck the object and the matter, can be sucked into the nozzle.  
      Furthermore, concerning the suction device of this invention, brushes can be placed in an attachable and detachable manner at the top end of the opening side of the nozzle. In addition to the aforementioned advantageous effects of the suction device, such attachment of the brushes to the top end of the opening side of the nozzle promotes the removal of the matter, such as dirt that is adhering to the object, by scraping and scrubbing the matter when expelling the fluid onto the matter to remove it.  
      Regarding the suction device of this invention, an elastic member can also be placed in an attachable and detachable manner at the top end of the opening side of the nozzle.  
      The present invention further provides a nozzle device comprising: a nozzle connected to a suction device; and a fluid nozzle placed within the nozzle and connected to a fluid injection device in order to expel a fluid toward the opening of the nozzle; wherein the nozzle device is structured in such a manner that: when the opening of the nozzle is unobstructed, the outside air sucked into the nozzle through its opening causes the fluid expelled out of the fluid nozzle to be pushed back and sucked into the nozzle from its base end without the fluid being ejected out of the nozzle; and when the amount of the outside air sucked into the nozzle is decreased by placing the opening of the nozzle close to or in contact with an object, the fluid expelled out of the fluid nozzle overcomes the outside air and is thereby ejected toward the object, and the fluid that has struck the object is sucked together with the outside air into the nozzle.  
      The nozzle device having the above-described structure can automatically expel the fluid toward the object merely by moving the nozzle close to the object or causing the nozzle to contact the object. It is also possible to automatically stop the fluid ejecting out of the nozzle by moving the nozzle away from the object.  
      Concerning the nozzle device of this invention, it is possible to form, in the vicinity of the opening of the nozzle, at least one small hole that can introduce outside air into the nozzle.  
      Moreover, the nozzle device of this invention can be structured in such a manner that a fluid injection hole of the fluid nozzle is located at a position recessed from the opening of the nozzle.  
      Regarding the nozzle device of this invention, brushes can be placed in an attachable and detachable manner at the top end of the opening side of the nozzle.  
      Furthermore, regarding the nozzle device of this invention, an elastic member can be placed in an attachable and detachable manner at the top end of the opening side of the nozzle.  
      The suction device of this invention has a simple structure. When conducting the suction operation, the suction device can cause the fluid to be automatically expelled out of the nozzle toward the object by means of a simple operation of placing the nozzle close to or in contact with the object, and can suck in the fluid that has struck the object. Moreover, the suction device has such an advantageous effect that it is possible to automatically stop the fluid ejecting out of the nozzle merely by moving the nozzle away from the object.  
      The nozzle device of this invention has a simple structure. When conducting the suction operation, the nozzle device can automatically expel the fluid toward the object by means of a simple operation of placing the nozzle close to or in contact with the object, and can suck in the fluid that has struck the object. Moreover, the nozzle device has such an advantageous effect that it is possible to automatically stop the fluid ejecting out of the nozzle by merely moving the nozzle away from the object. 
    
    
     DESCRIPTION OF DRAWINGS  
       FIG. 1  is a schematic view of a suction device on which a nozzle device is mounted according to Embodiment 1 of this invention.  
       FIG. 2  is a perspective view of the nozzle device of  FIG. 1 .  
       FIG. 3  is an enlarged sectional view of the principal part of the nozzle device shown in  FIG. 1 , where the suction device is activated, and the opening of the nozzle device is unobstructed.  
       FIG. 4  is an enlarged sectional view of the principal part of the nozzle device shown in  FIG. 1 , where the suction device is activated, and the opening of the nozzle device is closed by an object.  
       FIG. 5  is a perspective view of a nozzle device according to another embodiment of this invention.  
       FIG. 6  is a sectional view of an attachment attached to the top end of the nozzle device according to another embodiment of this invention.  
       FIG. 7  is a sectional view of a nozzle device according to Embodiment 2 of this invention, wherein the suction device is activated and the opening of the nozzle device is unobstructed.  
       FIG. 8  is a sectional view of the nozzle device of  FIG. 7 , wherein the suction device is activated and the opening of the nozzle device is closed by an object.  
       FIG. 9  is a front view of the nozzle device of  FIG. 7 .  
       FIG. 10  is a sectional view of the nozzle device as taken along line X-X of  FIG. 9   
    
    
     DETAILED DESCRIPTION  
      Preferred embodiments of the suction device and the nozzle device according to this invention are explained below with reference to the attached drawings. The following embodiments are described for purposes of illustration of this invention, and this invention is not limited to these embodiments. Therefore, this invention can be implemented in various manners unless such variations depart from the gist of the invention.  
     Embodiment 1  
       FIG. 1  is a schematic view of a suction device on which a nozzle device is mounted according to Embodiment 1 of this invention.  FIG. 2  is a perspective view of the nozzle device of  FIG. 1 .  FIG. 3  is an enlarged sectional view of the principal part of the nozzle device shown in  FIG. 1 , where the suction device is activated, and the opening of the nozzle device is unobstructed.  FIG. 4  is an enlarged sectional view of the principal part of the nozzle device shown in  FIG. 1 , where the suction device is activated, and the opening of the nozzle device is closed by an object.  
      Embodiment 1 is explained below by referring to an example in which the fluid is Water and the object is a wall.  
      As shown in FIGS.  1  to  4 , a suction device  1  of Embodiment 1 comprises a main suction device  100  and a nozzle device  10  detachably attached to the main suction device  100 .  
      Referring to  FIG. 1 , the main suction device  100  comprises: a main tank  120  capable of containing water  200  as the fluid; a filter unit  121  which is connected to the inside of the main tank  120  and filters the water  200  contained in the main tank  120 ; a pump  132  which is connected to the filter unit  121  and pumps up the water  200  filtered by the filter unit  121 ; a fluid supply tube  102  which is connected to the pump  132  and externally supplies the water  200  pumped up by the pump  132 ; a suction hose  101  which is connected to the main tank  120  and recovers the water  200  sprayed onto a wall  150 , together with the outside air  300 , into the main tank  120 ; a fan motor  141  which is connected to the main tank  120  and sucks in the air (outside air) contained in the main tank  120 ; a heater  160  which is connected to the main tank  120  and controls the temperature of the water  200  supplied through the filter unit  121  from the main tank  120 ; a control panel  170  for controlling the operation of the main suction device  100 ; and a base  180  capable of moving with all the described components mounted thereon.  
      The main tank  120  has a generally cylindrical shape which can be hermetically sealed, whose generally central part is hollow, and which possesses enough strength to withstand the suction by the fan motor  141 . On the top face (or ceiling plane) of the main tank  120 , a separator  143  is provided to separate a gas-liquid mixture introduced from the main tank  120  into a gas and a liquid according to the cyclone principle. The separated gas is sucked by the fan motor  141  via a duct  130 . This structure prevents water drops from entering the fan motor  141 . On the wall surface of the main tank  120 , the following components are mounted: a level gauge  123  by which the volume of the water  200  contained in the main tank  120  can be visually checked; the fluid supply tube  102 ; and hooks  124  for hanging the suction hose  101 .  
      The filter unit  121  is connected via a connecting hose  128  to the main tank  120 . This filter unit  121  comprises: a tank  126  into which the water  200  contained in the main tank  120  is supplied via the connecting hose  128 ; and a filter  127  which is placed within the tank  126  and filters the water  200 . This filter unit  121  is connected to the pump  132 .  
      The pump  132  is used to pump up the water  200 , which is contained in the filter unit  121  and is filtered by the filter  127 , and then to supply the water  200  from the top end of the fluid supply tube  102  to a fluid nozzle  12  of the nozzle device  10 , described later in detail. This pump  132  is connected to a pressure control unit  133  for controlling the pressure (water pressure) of the water  200  supplied to the fluid nozzle  12 . This pressure control unit  133  can control the pressure of the water (hot water)  200 , as desired, at the time of expelling the water  200  toward the wall  150 .  
      The pressure control unit  133  may be set so as to switch the pressure of the water  200  to be supplied to the fluid nozzle  12  among several stages, for example, “strongest,” “strong,” “slightly strong,” “moderate,” “slightly weak,” “weak,” and “weakest,” or an even more gradual control operation may be performed. It is possible to set the pressure control unit  133  so that the set pressure will be maintained unless it is intentionally changed. The operation of the pressure control unit  133  may be conducted by using a switch (not shown in the drawing) on the control panel  170  or by remote control with, for example, a controller.  
      The base end of the fluid supply tube  102  is connected to the heater  160  and the pump  132 , and then to the filter  127  of the filter unit  121 . The top end of the fluid supply tube  102  can be connected to the fluid nozzle  12  of the nozzle device  10  as described later in detail. This fluid supply tube  102  is secured to the suction hose  101  with fasteners  134 .  
      The base end of the suction hose  101  is connected to the main tank  120 , and is constructed in such a manner that the suction by the fan motor  141  causes the suction hose  101  to suck in the outside air  300  into the main tank  120 . The top end of the suction hose  101  can be connected to the nozzle  11  of the nozzle device  10  as described later in detail.  
      The fan motor  141  is connected to a suction control unit  142  for controlling the degree of vacuum (or suction force) of the fan motor  141 . This suction control unit  142  can control, as desired, the sucked amount (or air volume) of the outside air  300  sucked through the opening  13  of the nozzle  11  attached to the top end of the suction hose  101 . By controlling the suction force, the suction control unit  142  can achieve a balance between the pressure of the outside air  300  corresponding to the amount of the outside air sucked-in from the top end of the nozzle  11 , and the water pressure of the ejecting water  200 , and can prevent the water  200  from being externally discharged from the opening  13  of the nozzle  11  by means of the pressure of the sucked-in outside air  300 .  
      At the top end of the nozzle device  10 , the opening  13  capable of sucking in the outside air  300  is formed. The nozzle device  10  comprises the nozzle  11  whose base end can be connected to the suction hose  101 ; and the fluid nozzle  12  which is located inside the nozzle  11  and expels the water  200  toward the opening of the nozzle  11 .  
      The nozzle  11  comprises: a large-diameter part  14  in a generally cylindrical shape that can be connected to the suction hose  101 ; and a small-diameter part  15  in a generally cylindrical shape that is connected to the large-diameter part  14  and has a smaller diameter than that of the large-diameter part  14 . The large-diameter part  14  has a hollow structure, and the fluid nozzle  12  is placed in this hollow section. The small-diameter part  15  has a hollow section connected to the hollow section of the large-diameter part  14 , and is capable of causing the water  200  being expelled out of the fluid nozzle  12  to eject out of the nozzle  11  through the opening  13  formed at its top end.  
      Concerning Embodiment 1, the inside diameter of the small-diameter part  15 , that is, the diameter of the opening  13  (“ID” in  FIG. 3 ) was set to 10 mm, and the length of the small-diameter part  15  (“SL” in  FIG. 3 ) was set to 110 mm. Moreover, at the top end of the small-diameter part  15  (in the vicinity of the opening  13 ), a small hole which can introduce the outside air  300  into the nozzle  11  is formed. Concerning Embodiment 1, the diameter of this small hole  16  (“SD” in  FIG. 3 ) was set to 1.5 mm.  
      At the top end of the fluid nozzle  12 , an injection hole  17  for expelling the water  200  is formed, and the base end of the fluid nozzle  12  can be connected to the fluid supply tube  102 . The injection hole  17  faces the hollow section of the small-diameter part  16 , so that the water  200  being expelled out of the injection hole  17  passes through the hollow section of the small-diameter part  15  and ejects out of the opening  13 .  
      Regarding Embodiment 1, the position of the fluid nozzle  12  was set so that the distance between the injection part  17  and the boundary between the large-diameter part  14  and the small-diameter part  15  (“ML” in  FIG. 3 ) would become 10 mm. The hole diameter of the injection part  17  was set to approximately 0.5 mm.  
      The following description is about the detailed working of the suction device  1  according to Embodiment 1.  
      The nozzle  11  of the nozzle device  10  is first connected to the top end of the suction hose  101  of the main suction device  100 . The fluid nozzle  12  of the nozzle device  10  is connected to the top end of the fluid supply tube  102 . The nozzle device  10  is then attached to the main suction device  100 .  
      Subsequently, a specified amount of the water  200  is contained in the main tank  120 , and the control panel  170  is then operated to activate the fan motor  141 . Concerning Embodiment 1, the suction control unit  142  was used to set the degree of vacuum of the fan motor  141  to approximately 19 kPa. The activation of the fan motor  141  causes the outside air  300  to be sucked into the nozzle  11  through its opening  13  at the top end of the suction hose  101 . At this point, the amount of the outside air sucked into the nozzle  11  through its opening  13  is approximately 1.0 m 3 /min. This suction of the outside air  300  causes the air in the main tank  120  to be introduced into the separator  143 . Even if the water  200  is mixed with the air at this moment, the gas (air) will be separated from the liquid (water  200 ) within the separator  143  according to the cyclone principle, and the water  200  will not be sucked into the fan motor  141 . The outside air (or air) sucked by the fan motor  141  passes through the duct  130  and then through the fan motor  141 , and exits via a specified exhaust port.  
      At the same time, the control panel  170  is operated to activate the pump  132 . The activation of the pump  132  causes the water  200  contained in the filter unit  121  to be pumped up, and the heater  160  keeps the water  200  at a desired temperature. The water (hot water)  200  kept at a desired temperature is then supplied via the fluid supply tube  102  to the nozzle  12 . Concerning Embodiment 1, the pressure control unit  133  is used to set the water pressure of the pump  132  to approximately 0.3 MPa. At this point, the flow rate of the water  200  expelled out of the injection hole  17  of the fluid nozzle  12  is approximately 50 liters/hour.  
      In this state where the opening  13  of the nozzle  11  is unobstructed (see  FIG. 3 ), that is, where the nozzle  11  is placed away from the wall  150 , the outside air  300  being sucked into the nozzle  11  through its opening  13  collides with the water  200  being expelled out of the fluid nozzle  12  in the area between the injection hole  17  of the fluid nozzle  12  and the opening  13  of the nozzle  11 . The outside air  300  overcomes the water  200  being expelled out of the fluid nozzle  12 , and the water  200  will not be ejected out of the opening  13  of the nozzle  11 . Instead the water  200 , together with the outside air  300 , is sucked into the main tank  120  and recovered. Accordingly, it is not necessary to provide the nozzle device  10  with any complicated structure, such as a shielding plate as applied to conventional devices, in order to block the ejection of the water  200 . It is possible to block the ejection of the water  200  with the sucked-in outside air  300  so that the water  200  expelled out of the fluid nozzle  12  will not be ejected out of the opening  13  of the nozzle device  11 . Therefore, it is possible to simplify the structure of the nozzle, to lower the failure rate, and to inexpensively manufacture the nozzle.  
      When the opening  13  of the nozzle  11  is placed closed to or in contact with the wall  150  (see  FIG. 4 ) while maintaining the degree of vacuum of the fan motor  141  and the water pressure of the pump  132 , the amount of the outside air sucked into the nozzle  11  decreases as compared to that when the opening  13  of the nozzle  11  is unobstructed. At this point, the amount of the outside air sucked into the nozzle  11  is approximately 0.05 m 3 /min. Even if the opening  13  is closely pressed against the wall  150 , the outside air  300  will be introduced into the nozzle  11  via the small hole  16 . Accordingly, it is possible to move the nozzle device  10  smoothly and to recover the wastewater smoothly. A decrease in the amount of the outside air sucked into the nozzle  11  causes the water  200  being expelled out of the fluid nozzle  12  to overcome the outside air  300  being sucked into the nozzle  11  and to be ejected toward the wall  150 . Then, the water  200  that has struck the wall  150  is sucked into the main tank  120  and recovered, together with the outside air  300 , via the suction hose  101 .  
      If dirt or the like adheres to the wall  150 , the dirt will be removed by the water  200  being expelled on the wall  150  and will be sucked into the main tank  120  and recovered, together with the water  200  and the outside air  300 , via the suction hose  101 . Therefore, it is possible to suck in and remove the dirt easily and securely without causing the water  200  being expelled on the wall  150  to run down or drip onto a user&#39;s clothes, bedding, floors or the like making them wet.  
      As a result of the above-described action, both the recovered liquid and the clean water  200  that has been housed from the beginning will be put in the main tank  120 . The operation of the pump  132  causes the water  200  that has been housed in the main tank  120  and the water  200  recovered into the main tank  120  to be supplied to the filter unit  121 , where the mixture is filtered by the filter  127 , and the filtered water  200  is then supplied again through the fluid supply tube  102  to the fluid nozzle  12 .  
      If the opening  13  of the nozzle  11  in the above condition is moved away from the wall  150  (that is, the opening  13  of the nozzle  11  is unobstructed), the amount of the outside air sucked into the nozzle  11  through its opening  13  increases again. In the area between the injection hole  17  of the fluid nozzle  12  and the opening  13  of the nozzle  11 , the sucked-in outside air  300  collides with the water  200  being expelled out of the fluid nozzle  12 . As a result, the outside air  300  overcomes the water  200  being expelled out of the fluid nozzle  12 , and the water  200  will not be ejected out of the opening  13  of the nozzle  11 , but will be sucked into the main tank  120  and recovered, together with the outside air  300 .  
      Concerning Embodiment 1, the case in which water (hot water) is used as the fluid has been described. However, the fluid is not limited to water, and any fluid can be selected as desired, depending on the purpose of use. Examples of the fluid include water vapor, alkaline cleaning solvents or much stronger alkaline cleaning solvents, chlorine cleaning solvents such as bleaching agents or fungicides, neutral detergents, alcohol disinfectants, beauty products (such as toners, cosmetic essence, or moisture lotions), or solutions or vapors containing aromatic essence. It is also possible to choose the temperature, spray amount, and other conditions of the fluid as appropriate, according to the type and purpose of use of the fluid.  
      Moreover, concerning Embodiment 1, the case in which the inside diameter (ID) of the small-diameter part  15 , that is, the inside diameter of the opening  13  was set to 10 mm, and the length of the small-diameter part  15  was set to 110 mm has been described. However, the size of the small-diameter part  15  is not limited to the above-described size. Both the inside diameter (ID) and the length (SL), or either one of them, of the small-diameter part  15  can be decided, as desired, according to the water pressure of the water  200  being expelled out of the fluid nozzle  12 , as long as the following results are obtained: when the opening  13  of the nozzle  11  is unobstructed, the outside air  300  being sucked into the nozzle  11  through its opening  13  can overcome the pressure of water  200  being expelled out of the fluid nozzle  12 , and the water  200  can be sucked in together with the outside air  300  without the water  200  being ejected out of the opening  13  of the nozzle  11 ; and when the opening  13  of the nozzle  11  is placed close to or in contact with the wall  150  to cause the amount of the outside air sucked into the nozzle  11  to decrease, the water  200  being expelled out of the fluid nozzle  12  can overcome the pressure of the outside air  300  and is ejected toward the wall  150 , and the water  200  that has struck the wall  150  can be sucked in together with the outside air  300 .  
      Furthermore, this invention has been described about the case in which the degree of vacuum of the fan motor  141  is set to become approximately 19 kPa and the water pressure of the pump  132  is set to become approximately 0.3 MPa. However, the degree of vacuum of the fan motor  141  and the water pressure of the pump  132  are not limited to the above settings, and can be decided as desired, as long as the following results are obtained: when the opening  13  of the nozzle  11  is unobstructed, the water  200  can be sucked in together with the outside air  300  without the water  200  being ejected out of the opening  13  of the nozzle  11 ; and when the opening  13  of the nozzle  11  is placed close to or in contact with the wall  150  to cause the amount of the outside air sucked into the nozzle  11  to decrease, the water  200  being expelled out of the fluid nozzle  12  can be ejected toward the wall  150 , and the water  200  that has struck the wall  150  can be sucked up.  
      Furthermore, concerning Embodiment 1, the case in which the diameter of the small hole  16  was set to 1.5 mm has been described. However, the diameter of the small hole  16  is not limited to the above setting, and can be decided as desired as long as the following results are obtained: when the opening  13  of the nozzle  11  is closely pressed against the wall  150 , the nozzle  11  can be moved smoothly in relation to the wall  150 ; and when the opening  13  of the nozzle  11  is unobstructed, the water  200  can be sucked in together with the outside air  300  without the water  200  being ejected out of the opening  13  of the nozzle  11 ; and when the opening  13  of the nozzle  11  is placed close to or in contact with the wall  150  to cause the amount of the outside air being sucked into the nozzle  11  to decrease, the water  200  being expelled out of the fluid nozzle  12  can be ejected toward the wall  150 , and the water  200  that has struck the wall  150  can be sucked up. Similarly, it is also possible to set the number of the small holes  16  as desired.  
      Furthermore, if any material, such as a curtain that can allow passage of the outside air to some extent, or a wall that has a pattern-indented surface, is adopted as the object, even if the nozzle  11  is closely pressed against the material, a certain amount of the outside air will be introduced into the nozzle  11 . Therefore, it is not always necessary to form the small hole  16 .  
      Concerning Embodiment 1, the case in which the hole diameter of the injection part  17  was set to approximately 0.5 mm has been described. However, the hole diameter of the injection part  17  is not limited to the above setting, and can be decided as desired as long as the following results are obtained: when the opening  13  of the nozzle  11  is unobstructed, the water  200  can be sucked in together with the outside air  300  without the water  200  being ejected out of the opening  13  of the nozzle  11 ; and when the opening  13  of the nozzle  11  is placed close to or in contact with the wall  150  to cause the amount of the outside air sucked into the nozzle  11  to decrease, the water  200  being expelled out of the fluid nozzle  12  can be ejected toward the wall  150  and the water  200  that has struck the wall  150  can be sucked up.  
      Moreover, the shape and the size of the nozzle  11  are not limited to those explained in Embodiment 1, and can be decided as desired, according to the part of the object, on which the nozzle  11  should be used, and according to the usage conditions.  FIG. 5  shows an example in which the nozzle  11  is a hollow body that is slightly bent down. The shape of the fluid nozzle  12  can also be decided as desired, corresponding to the shape of the nozzle  11  as shown in  FIG. 5 .  
      Regarding another embodiment, as shown in  FIG. 6 , a cylindrical projection  21  with a small diameter may be further formed at the top end of the small-diameter part  15  of the nozzle, and an attachment  20  may be placed on the projection  21  in an attachable and detachable manner. The base end of the attachment  20  is formed as a fitting part  22  that can be detachably attached to the projection  21  of the nozzle  11 . On the top-end surface of the fitting part  22 , brushes  23  are implanted. Moreover, around the periphery of the fitting part  22 , a rubber sheet  24  is attached so as to surround the brushes  23 .  
      When the nozzle  11  is placed close to or in contact with the wall  150  and the water  200  is caused to be ejected to remove the matter such as dirt that is adhering to the wall  150 , the brushes  23  are used to improve the removal of the matter by scraping or scrubbing.  
      The rubber sheet  24  serves to decrease the amount of the outside air sucked into the nozzle  11  when the nozzle  11  is placed close to or in contact with the wall  150 . In other words, if the attachment only with the implanted brushes  23  were used, the outside air  300  would freely enter the nozzle  11  between the brushes  23  and, therefore, it would be difficult to decrease the amount of the outside air sucked into the nozzle  11 . However, if the periphery of the brushes  23  is surrounded with the rubber sheet  24 , it is possible to easily decrease the amount of the outside air sucked into the nozzle  11 . This rubber sheet  24  has moderate elasticity and flexibility and is thereby capable of following the movement of the brushes  23 . Therefore, the rubber sheet  24  will not hinder the movement of the brushes  23  when scraping and scrubbing the matter.  
     Embodiment 2  
      Embodiment 2 of this invention is described below with reference to the relevant drawings.  
       FIG. 7  is a sectional view of a nozzle device according to Embodiment 2 of this invention, wherein the suction device is activated and the opening of the nozzle device is unobstructed.  FIG. 8  is a sectional view of the nozzle device of  FIG. 7 , wherein the suction device is activated and the opening of the nozzle device is closed by an object.  FIG. 9  is a front view of the nozzle device of  FIG. 7 .  
      The elements of Embodiment 2 which are similar to the elements described in Embodiment 1 are given the same reference numerals as in Embodiment 1, and any detailed description of such elements is omitted.  
      As shown in FIGS.  7  to  9 , a nozzle device  30  of Embodiment 2 is different from the nozzle device  10  of Embodiment 1 in the shape of a nozzle  31 . At the top end of this nozzle device  30 , an opening  33  capable of sucking in the outside air  300  is formed. The nozzle device  30  comprises: the nozzle  31  whose base end can be connected to the suction hose  101 ; and the fluid nozzle  12  which is located within the nozzle  31  and ejects the water  200  toward the opening of the nozzle  31 .  
      The nozzle  31  comprises: a cylindrical part  34  in a generally cylindrical shape which can be connected to the suction hose  101 ; and a fan-like part  35  in a generally fan shape which is connected to the cylindrical part  34  and whose diameter becomes gradually larger from its base end, which is connected to the cylindrical part  34 , toward its top end.  
      The cylindrical part  34  has a hollow structure, and the fluid nozzle  12  is located in this hollow section. The top end of the fluid nozzle  12  extends to the base end of the fan-like part  35 . The fan-like part  35  has a hollow section connected to the hollow section of the cylindrical part  34 , so that the water  200  being expelled out of the top end of the fluid nozzle  12  can be ejected out of the opening  33  formed at the top end of the fan-like part  35 . This opening  33  is generally rectangular as specifically shown in  FIG. 9 . Moreover, at the top end of the fan-like part  35  (in the vicinity of the opening  33 ), two small holes  16  which can introduce the outside air  300  into the nozzle  31  are formed.  
      Concerning Embodiment 2, the fan angle (“a” in  FIG. 7 ) is set to 115 degrees, the length of the long side of the opening  33  (“LS” in  FIG. 9 ) is set to 100 mm, and the length of the short side of the opening  33  (“SS” in  FIG. 9 ) is set to 4 mm. The distance between the injection hole  17  of the fluid nozzle  12  to the opening  33  (“FL” in  FIG. 7 ) is set to 45 mm. The diameter of the small hole  16  (“SD” in  FIG. 7 ) is set to 1 mm.  
      The following description is about the detailed working of the suction device  1  according to Embodiment 2.  
      In the same way as in Embodiment 1, the nozzle  31  of the nozzle device  30  is first connected to the top end of the suction hose  101  of the main suction device  100 . The fluid nozzle  12  of the nozzle device  30  is connected to the top end of the fluid supply tube  102 . The nozzle device  30  is then attached to the main suction device  100 .  
      Subsequently, the fan motor  141  is activated under the same conditions as in Embodiment 1 to suck in the outside air  300  from the opening  33  of the nozzle  31  attached to the top end of the suction hose  101 . At the same time, the pump  132  is activated to supply the water (hot water)  200  via the fluid supply tube  102  to the fluid nozzle  12 .  
      Concerning Embodiment 2, the pressure control unit  133  is used to set the water pressure of the pump  132  to approximately 3 kg/cm 2 . At this point, the water  200  expelled out of the injection hole  17  of the fluid nozzle  12  formed an injection angle of 115 degrees and the injection rate was approximately 0.4 liters/min.  
      In this state where the opening  33  of the nozzle  31  is unobstructed (see  FIG. 7 ), that is, where the nozzle  11  is placed away from the wall  150 , just like in the case of Embodiment 1, the outside air  300  being sucked into the nozzle  31  through its opening  33  collides with the water  200  being expelled out of the fluid nozzle  12  in the area between the injection hole  17  of the fluid nozzle  12  and the opening  33  of the nozzle  31 . The outside air  300  overcomes the water  200  being expelled out of the fluid nozzle  12 , and the water  200  is not ejected out of the opening  33  of the nozzle  31 . Instead, the water  200 , together with the outside air  300 , is sucked into the main tank  120  and recovered.  
      Subsequently, when the opening  33  of the nozzle  31  is placed closed to or in contact with the wall  150  (see  FIG. 8 ) while maintaining the degree of suction vacuum of the fan motor  141  and the water pressure of the pump  132 , just like in the case of Embodiment 1, the amount of outside air sucked into the nozzle  31  decreases as compared to that when the opening  33  of the nozzle  31  is unobstructed. The water  200  being expelled out of the fluid nozzle  12  overcomes the outside air  300  being sucked into the nozzle  31 , and is ejected toward the wall  150 . Then, the water  200  that has struck the wall  150  is sucked into the main tank  120  and recovered, together with the outside air  300 , via the suction hose  101 . If dirt or the like is adhering to the wall  150 , just like in the case of Embodiment 1, the dirt will be removed by the water  200  being expelled on the wall  150  and will be sucked into the main tank  120  and recovered, together with the water  200  and the outside air  300 , via the suction hose  101 .  
      If the opening  33  of the nozzle  31  in the above condition is moved away from the wall  150  (that is, the opening  33  of the nozzle  31  is unobstructed), the amount of outside air sucked into the nozzle  31  through its opening  33  again increases. In the area between the injection hole  17  of the fluid nozzle  12  and the opening  33  of the nozzle  31 , the sucked-in outside air  300  collides with the water  200  being expelled out of the fluid nozzle  12 . As a result, the outside air  300  overcomes the water  200  being expelled out of the fluid nozzle  12 , and the water  200  is not ejected out of the opening  33  of the nozzle  31 . Instead, the water  200  will be sucked into the main tank  120  and recovered, together with the outside air  300 .  
      By using the nozzle  31  having the above-described structure, it is possible to expel the water  200  over a wide range of the wall  150 , thereby enabling efficient suction operation.  
      Regarding Embodiment 2, the description has been given about the case in which the fan angle α of the fan-like part  35  was set to 115 degrees, the length of the long side of the opening  33  (“LS” in  FIG. 9 ) was set to 100 mm, and the length of the short side of the opening  33  (“SS” in  FIG. 9 ) was set to 4 mm. However, the fan angle, the length of the long side, and the length of the short side are not limited to the above settings, and can be decided as desired, according to the water pressure of the water  200  being expelled out of the fluid nozzle  12 , as long as the following results are obtained: when the opening  33  of the nozzle  31  is unobstructed, the outside air  300  being sucked into the nozzle  31  through its opening  33  can overcome the pressure of the water  200  being expelled out of the fluid nozzle  12 , and the water  200  can be sucked up together with the outside air  300  without the water  200  being ejected out of the opening  33  of the nozzle  31 ; and when the opening  33  of the nozzle  31  is placed close to or in contact with the wall  150  to cause the amount of outside air sucked into the nozzle  31  to decrease, the water  200  being expelled out of the fluid nozzle  12  can overcome the pressure of the outside air  300  and is ejected toward the wall  150 , and the water  200  that has struck the wall  150  can be sucked up.  
      Moreover, just like in the case of Embodiment 1, the attachment as shown in  FIG. 6  can be placed, in an attachable and detachable manner, at the nozzle device  30  of Embodiment 2.