Conventionally, liquid dilution devices are widely used to mix a special liquid such as a chemical liquid or detergent with tap water, for sterilization or disinfection when rinsing tableware or fresh vegetables. As disclosed in Japanese Patent No. 3149166 and so on, for example, the conventional liquid dilution device includes inside a body, a diluent passage for allowing passage of water (tap water), a negative pressure generate section formed in order to generate negative pressure somewhere along the diluent passage, and a liquid introduce passage connected at one end to the negative generate section and connected at the other end to a special liquid tank. By allowing a liquid, such as water or the like, into the diluent passage, negative pressure is generated at the negative pressure generate section. By this negative pressure, the special liquid is introduced from a special liquid tank into the diluent passage, and the special liquid is mixed with the water flowing in the diluent passage and thus is diluted.
Since it is desired for such a liquid dilution device to change the dilution factor depending on the special liquid, various methods for changing the dilution factor have been devised. For example, one design that was devised was to fix a jet in a hose connecting the special liquid tank to the liquid dilution device, and interchange the jets depending on the special liquid. However there is a problem that the interchanging of the jets by a user is inferior in efficiency and interchangeability.
Therefore, another design was devised to provide a dilution factor switching means in the liquid dilution device itself. A liquid dilution device of the related art provided with a dilution factor switching means is shown in FIG. 8 and FIG. 9, and the dilution factor switching means is shown in FIG. 10. One diluent passage 61 is formed inside the body 60, for introducing a diluent such as water. The diluent passage 61 includes a venturi section 62 formed at some midstream as a negative pressure generate section, and a diffusion section 63 formed at a downstream side of this venturi section 62 as a negative pressure generate section having a diameter larger than that of the venturi section 62. In the body 60, a connect passage 64 which connects the diffusion section 63 to the outer side of the body 60 is formed.
A disk 66, as the dilution factor switching means, which is sandwiched by the body 60 and a holding member 65, is provided on the outer side of the body 60 at the side of an opening section of the connect passage 64. The disk 66 is rotatably attached to the body 60 and the holding member 65 through a bearing 68, centering around a shaft (bolt) 67 which is a fixing means for fixing the holding member 65 to the body 60. As shown in FIG. 10, a plurality of jets 69, respectively varying in diameter, are formed at the disk 66 on the same radius from a rotation center position.
In addition to the holding member 65, a liquid introduce device 70 is provided on the opposite side of the body 60 to sandwich the disk 66. Then, the liquid introduce device 70 is fixed to the body 60. The liquid introduce device 70 includes a first body 71 and a second body 72. A liquid supply passage 73 connecting to a special liquid tank, not shown in the figure, is formed inside the first body 71 and the second body 72. The liquid supply passage 73 is connected to the diluent passage 61 through the jet 69 formed in the disk 66 and the connect passage 64 of the body 60.
A ring-shaped seal member 74 is attached at a position of the body 60 facing the disk 66 and surrounding the connect passage 64. The ring-shaped seal member 74 is for preventing leakage of water from a joint surface of the body 60 and disk 66 passing through the diluent passage 61 and the connect passage 64. A ring-shaped seal member 75 is attached at a position of the first body 71 of the liquid introduce device 70 facing the disk 66 and surrounding the liquid supply passage 73. The ring-shaped seal member 75 is for preventing leakage of a special liquid from a joint surface of the first body 71 of the liquid introduce device 70 and the disk 66 passing through the liquid supply passage 73. An elastic member 76 is provided at a position of the body 60 facing the disk 66 and being far from the seal member 74. An elastic member 77 is provided at a position of the holding member 65 facing the disk 66 and with some distance from the seal member 75. These elastic members 76 and 77 prevent the disk 66 from leaning towards either the body 60 or the holding member 65.
By lining up one of the plurality of jets 69 formed in the disk 66 to the connect passage 64 of the body 60, the connect passage 64 of the body 60 and the liquid supply passage 73 of the liquid introduce device 70 are connected through the jet 69. In this manner, when the connect passage 64 and the liquid supply passage 73 are connected through the jet 69, the special liquid is introduced from the liquid supply passage 73 into the diluent passage 61 by negative pressure generated in a diffusion section 63 of the diluent passage 61. Here, it is possible to vary the flow amount of the special liquid introduced into the diluent passage 61 so as to change the dilution factor, by rotating the disk 66 to line up one of the plurality of jets 69 with the connect passage 64 and the liquid supply passage 73.
With the dilution factor switching means 66 having the plurality of jets 69 for adjusting flow amount, when a certain time passes after the jet 69 is once used, there arises a problem that the desired dilution factor cannot be obtained because the special liquid may dry out and stick to the jet 69, or the jet 69 may be choked.
The present invention was devised in the light of the abovementioned problem. The object of the present invention is to provide a liquid dilution device which can prevent a jet for adjusting flow amount of the special liquid from adjusting changes or choking.