Abstract:
With the dispenser the flow rate of detergent can be adjusted in accordance with the water flow rate. The dispenser comprises an aspiration conduit connected to the expansion chamber of an ejector by a channel fashioned radially on a head of the aspiration conduit. The height of the channel can be changed by rotating the head with respect to the body of the dispenser.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a water cleaner in which the operator can easily regulate the quantity of a detergent which is dispensed in relation to a quantity of water delivered. 
   In the field of equipment and spray-guns for water-cleaners, the prior art teaches application downstream of the gun of devices for injecting a predetermined dose of detergent into the water. 
   These devices aspirate detergent from a special container employing a Venturi-type effect, in which a depression is created in an expansion chamber as a result of the velocity of the water pumped by the cleaner. 
   The prior art also includes devices enabling a regulation of the delivery of the detergent, i.e. a change in ratio between aspirated detergent delivery and water delivery. 
   These known devices are generally constituted by a calibrated nozzle inserted in the detergent aspiration conduit, the nozzle being interchangeable. Thus by changing the nozzle the detergent flow rate is also changed. 
   Other known detergent dispensers with regulatable delivery include a vacuum-breaker valve on the expansion chamber. The vacuum-breaker can be calibrated, so the degree of vacuum can be varied in the expansion chamber and therefore the aspirated detergent fluid can also be regulated. 
   The above-described devices present various drawbacks. Firstly, the nozzles inserted on the detergent aspiration conduit are subject to blockages during operation, reducing or even interrupting delivery of the detergent. 
   Further, it is a nuisance to have to substitute the nozzle according to the detergent and flow rate required, as it involves having replacement nozzles to hand, which is not always the case with water cleaning apparatus. 
   Finally, it is not immediately obvious which nozzle is installed due to poor legibility from the outside, so the flow rate ratio, i.e. the ratio between the detergent and water delivery, is not evident unless the nozzle is first dismounted and/or replaced. 
   In the case of regulation devices equipping vacuum-breaker valves, there is a risk of blockage or loss of accuracy, but especially there is a lack of precision in determining the exact value of the desired dispensing ratio. 
   SUMMARY OF THE INVENTION 
   The main aim of the present invention is therefore to obviate the above-cited drawbacks present in the prior art, by providing an adjustable detergent dispensing device for water cleaners which has no need of substitution of parts when the flow rate of the detergent is to be changed (i.e. in the change of water/detergent ratio), and in which the selected ratio is clearly legible, and which is easily washable to remove the deposits which inevitably build up in the aspirating conduits due to using a detergent. 

   
     BRIEF DESCRIPTION of the DRAWINGS 
     These and other aims besides are all attained by a regulatable detergent dispensing device for water cleaners, as it is described in the appended claims. Further characteristics and advantages of the present invention will better emerge from the detailed description that follows of a preferred but non-exclusive embodiment of the invention, illustrated purely by way of non-limiting example in the accompanying figures of the drawings, in which: 
       FIGS. 1A ,  1 B and  1 C show, in a vertical axial plane and in section, the three parts which constitute the device, represented in dismounted position according to the vertical insertion axis, and respectively constituted by the body of the device, the aspiration conduit with upper head, and a recipient for containing detergent; 
       FIG. 2  shows, in a vertical axial plane, and in section, an enlarged detail of the body of the device of  FIG. 1A , and the head of the aspiration conduit of  FIG. 1B , correctly mounted in operating configuration; 
       FIG. 3  is a view of the body of the device of  FIG. 1A  seen from plane A—A in  FIG. 1A ; 
       FIG. 4  is a view from above of the head of the aspiration conduit of  FIG. 1B ; 
       FIGS. 5A ,  5 B,  5 C each show a detail of the aspiration conduit head of  FIG. 1B , respectively shown vertically sectioned along lines B—B, C—C and D—D. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the figures of the drawings,  1  denotes the body of the device in its entirety;  2  denotes a threading for connection to a water-gun, not shown in the figures. 
     3  denotes a tapered chamber for containing water under pressure, which ends with a fixed nozzle  4 ; together, the chamber  3  and the nozzle  4  constitute a water ejector. 
     5  denotes an expansion chamber in which, by a Venturi effect, a depression is caused by action of an exiting jet from the nozzle  4 . 
     6  represents a nozzle and  7  a delivery mouth for the jet. 
     8  denotes a hole connecting the expansion chamber  5  with an underlying chamber  9  delimited by the trunco-cylindrical wall  10 . 
     11  denotes a series of notches, arranged in diametrically-opposite couples on the lower edge of the trunco-cylindrical wall  10 . The notches  11  are destined to contact respectively with a pair of teeth  20  fashioned on the aspiration conduit  15  head  16 , when the aspiration conduit  15  is placed in operating position on the device. 
     12  denotes a lower connecting portion of the body  1 , destined to connect in a bayonet joint with teeth  29  located on the neck  30  of the detergent container  31 . 
   A numbered scale (numbered from  1  to  6 , the numbers being equidistanced) is located on the lower edge  13  of the connecting portion  12 . 
   The head  16  of the aspiration conduit  15 , shown in detail in  FIGS. 4 and 5 , is constituted by: a wide plate  17 , destined to contact against the trunco-cylindrical wall  10 ; by a trunco-cylindrical drum  18  an external wall of which exhibits an o-ring  19  made of an elastomer material; and by a flat upper part  21  on which radial channels  22 A,  22 B,  22 C,  22 D and  22 E are afforded, having different depths and being angularly equidistanced radially and being of a number which corresponds to the numbering written on the lower edge  13  of the connecting portion  12 . In the illustrated embodiment, the channels are 5 in number, as there are 6 numbers on the lower edge  13  (a sixth number being zero). 
   The aspiration conduit  15  is internally hollow and exhibits an axial hole  23 , while externally the aspiration conduit  15  exhibits a fixed tab  24  which indicates the angular position of the aspiration conduit  15 . 
   The container  31  of detergent, which can be variously shaped in a main body thereof, at a top thereof exhibits a rigid neck  30  having two joint teeth  29  and a collar  28  which, when the apparatus is assembled, contacts against the internal part of the lower edge  13  of the connecting portion  12 . 
   The above prevalently structural description is now followed by a description of how the invention operates. 
   Starting from the disassembled situation, represented in  FIGS. 1A ,  1 B and  1 C, the operator first inserts the aspiration conduit  15  into the chamber  9  of the body  1  of the device, coupling the drum  18  on the walls  10  of the chamber  9 . This coupling is solid thanks to the action of the o-ring  19  on the head of the drum  18 , which exerts a mechanical gripping action on the body  1  and the drum  18  as well as a hydraulic sealing action. 
   The coupling also causes the teeth  20  to couple with a pair of notches  19  in a variety but limited number of positions, which in the embodiment are six in number. 
   The positions are indicated by the position of the tab  24  with regard to the numbers written on the circular crown of the lower edge  13 ; thus it is easy to know the angular position in which the head  16  of the aspiration conduit  15  has been installed on the chamber  9 . 
   This tab position indicates a situation in which of one of the channels  22 A,  22 B,  22 C,  22 D,  22 E coincides with the hole  8  giving access to the expansion chamber  5 . 
   A sixth position is provided, in which there is no coinciding channel  22 . This means that in the sixth position the hole  8  is stopped, and the tab at this position will be aligned with position number  0 . 
   Finally the operator inserts the neck  30  of the container  31  on the connecting portion  12 , closing the bayonet joint with the teeth  29 . 
   This operation is possible only if the teeth  20  have correctly entered into one of the pair of notches  11 . For this reason, the upper edge  25  of the neck  30  strikes against the plate  17 , obliging it to settle in the correct position. 
   The closure position of the neck  30  is illustrated in  FIG. 2 . 
   Should the teeth  20  not enter the notches  19 , the bayonet joint involving the teeth  29  of the container neck  30  and the notches  14  will not be properly effected; also, the collar  28  would not perfectly settle on the lower edge  13 . 
   Pressurised water can be introduced into the chamber  3 , causing aspiration of the detergent in the pathway connecting the hole  8  with the aspiration conduit  23  through the preselected channel  22 . 
   As the depth of the channels  22  is different, according to the angular position of the conduit  15  the flow rate of the aspirated detergent will be different, as the loss of head in the channel  22  will be of different entities. The height of the channels  22  is comprised in an interval going from 0 (position zero) to 1 mm (deepest channel). 
   Alternatively to a multiplicity of radial channels  22  having different depths, it would be possible to have a continuous variation in the height of the aspiration conduit head  16  at a channel  22  according to the angular position of the conduit  15 . This is obtained by helically shaping the upper part  21  in a wide radial arch shape, starting, for example, from level  0  (zero) and going up to the maximum depth of the deepest channel  22 . This would give rise to a helical space between the aspiration conduit head  16  and the body  1  at the chamber  9 ; and this would lead to a variable height in the helical space at the base of the hole  8 , and therefore a different loss of head of the detergent in that zone. 
   The aim of enabling selection of the most suitable flow rate value is thus achieved, with a simple mounting operation in the desired position of the conduit  15 . It is also easy to clean the channels  22  of the connecting conduit between the expansion chamber  5  of the ejector and the aspiration conduit  15 , as the latter part can be mounted and dismounted easily from the body  1  of the device.