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FIELD OF THE INVENTION 
     The present invention relates to quantitative liquid dispensers, which employ a suction disc for mounting in a water vessel, such as a toilet tank whose level of water is changing from an upper level to a lower lever and vice versa. The dispenser of this invention is capable to dispense a fix volume of concentrate cleansing liquid and dilute the liquid in a buffer chamber for a sanitary system. 
     BACKGROUND OF THE INVENTION 
     Conventional automatic sanitary methods for toilet bowl can be categorized in two types: 
     One type is to mount a toilet rim dispenser that contains cleansing block, cleansing jelly or cleansing concentrate liquid. Flush water flows over the dispenser and carries the detergents into the toilet for cleaning. Because the dispenser is hung inside the toilet, it occupies space, is not slightly, and gives people unsanitary impression. Moreover, the hanging band or hook makes the toilet seat tilted unevenly, and some toilet designs and constructions are not suitable for hanging dispensers. 
     Another type of cleaning method is directly placing cleansing block into the toilet tank. It has disadvantages of poorer cleaning effect; color pigments are added to the detergents to function as indicators, and there is no strong fragrance. Moreover, the cleansing blocks are blended with a full tank of water, and result in fast decomposition. They are dissolved and consumed rapidly even when the toilet is not being used. There is a self-lasting life when placed in toilet tank. It causes a lot of waste. 
     SUMMARY OF THE INVENTION 
     In view of aforesaid disadvantages, the primary object of the invention is to provide an automatic sanitary dispenser that is held in the water tank of a toilet. The sanitary dispenser of the invention is hung through a sucking disc without hooks. Thus there are not concerns of installation height and location for the dispensers that incur to tank rim hanging type dispensers. It may be adaptable to any types of toilet tanks. Volumetric concentrate liquid of specific fragrance and cleansing property is dispensed in a dilute buffer chamber and is diluted quantitatively with water. A flat and elongate hollow dispensing probe is provided to control water intake and discharge and to completely isolate the diluted solution. The dispensing probe has an inlet/outlet mean submerging in the bottom section of the toilet tank. The dilute buffer chamber is located on the upper portion of the dispensing probe and has two openings to communicate with the dispensing probe. During toilet flushing, this predetermined quantitatively diluting liquid is discharged into the toilet. Only a small amount of diluted detergents are retained in the water tank and blended with water. The dispenser of the invention consumes only a small amount of concentrate detergents for every. flush, and most of the dilute detergents are flushed into the toilet. 
     When the dispenser of the invention is used in the water tank of a toilet, based on fragrance and foaming condition, users may be aware when to replenish the concentrate detergents. When the toilet is in automatic flush operation, the preferable method is to flush clean water first, then flush with detergents such that the detergents may be retained in the toilet to achieve optimum cleaning and sanitary effect. 
    
    
     The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a liquid dispenser of the invention, showing a liquid bottle and a sucking disc. 
     FIG. 2 is a perspective view of a liquid bottle of the invention. 
     FIG. 3 is an exploded view of the invention. 
     FIG. 4 is a front view of a liquid dispenser of the invention. 
     FIG. 5 is a perspective view of a float quantitative device of the invention. 
     FIG. 6 is an exploded sectional view of a float quantitative device of the invention. 
     FIG. 7 is a front view, partly cutaway, of an inlet/outlet mean of the dispensing probe of the invention. 
     FIG. 8 is a perspective view of yet another embodiment of the dispenser of the invention. 
     FIG. 9 is a front view of yet another embodiment of the dispenser of the invention. 
     FIG. 10 is a side view of yet another embodiment of the. dispenser of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Refer to FIG. 1 for a liquid dispenser  1  of the invention. It mainly consists of a liquid bottle  2 , a dispensing probe  3 , a dilute buffer chamber  4 , a float quantitative device  5 , a sucking disc  6  and an anchor disc  7 . 
     The liquid bottle  2  (also referring to FIG. 2) is a hollow box type container and has a seal cap  20  located on a bottom end thereof. The bottom section of the seal cap has a crack opening  21  which may be cracked and opened by under compression. 
     The dispensing probe  3  is an elongate, flat and hollow box type member formed substantially in a T shape. At the upper section, there are a lower opening  35  and an upper opening  36  (referring to FIGS.  3  and  4 ). At the bottom end of the dispensing probe  3 , there is an inlet/outlet  30 . The bottom end has a pair of partitions  31  to form a U-shaped pressure trap passage  32  consisting of two symmetrical U-shaped channels. Water or dilute solution may pass. into or outside the dispenser through the inlet/outlet  30 . The top end of the dispensing probe  3  has two air vents  33  and forms substantially a cap in an inverse U shape with two gaps  34  formed on two sides thereof such that the air vents  33  have the openings directing downwards at two sides thereof. 
     Referring to FIGS. 3 and 4, the dilute buffer chamber  4  is a box type container for diluting concentrate liquid. On a lateral side of the dilute buffer chamber, there are two openings located respectively at an upper elevation and a lower elevation to bond tightly and communicate with the upper opening  36  and the lower opening  35  of the dispensing probe  3 . The dilute buffer chamber  4  has a top end with an capsule opening  40  formed thereon and an anchor notch  41 . The float quantitative device  5  includes a base dock  50  and a quantitative float barrel  51  (also referring to FIGS. 3,  4 ,  5  and  6 ). The quantitative float barrel  51  is housed in the dilute buffer chamber  4  through the capsule opening  40 . The base dock  50  is engaged tightly with the capsule opening  40 . The base dock  50  has an indented trough  500  formed on the upper section. There is a liquid channel tube  501  extending upwards from the center of the indented trough  500 . The top end of the channel tube  501  forms a sharp opening  502  and a notch  503  to prevent blocking of the liquid inlet. The bottom section of the channel tube  501  connects to a cylindrical drip tube  504  which has a bottom end with an outlet  505  formed thereon to allow concentrate liquid to flow out. The drip tube  504  has an aperture  506  formed on the side wall thereof. The lower end of the drip tube  504  couples with the quantitative float barrel  51  which may be moved only up or down. The quantitative float barrel  51  has a cylindrical trough  510  and opening  511  to match and couple with the drip tube  504 . The bottom end of the quantitative float barrel  51  forms a full opening  512 . 
     Referring to FIG. 7, when water flows in, A, B, and C represent water levels. (A-B) represents differential liquid pressure between A and B, and (B-C) represents differential liquid pressure between B and C. When water level outside the dispensing probe  3  is greater than [B+(B-C)−(A-B)], water starts overflowing the point B and enters into the dispensing probe  3  through the inlet/outlet  30 , and water level starts to rise continuously and flows into the dilute buffer chamber  4  through the two openings at the upper and lower elevation that communicate with the dispensing probe  3 ; water level continues to rise and reaches the upper opening  36  of the dispensing probe  3  to communicate with the dispensing probe  3 . D represents the lowest working water level of the water tank for the liquid dispenser  1 . E represents the normal working water level. When in use, if water level exceeds point E and submerges the air vents  33 , the liquid dispenser  1  still can function properly. When water intake is completed and water level becomes still, a selected amount of water flows into the liquid dispenser  1  to blend with detergents to form diluted detergent liquid. After water intake, dissolved diluted liquid may be held still for a long period of time (more than two weeks) without flowing out through the inlet/outlet  30  at the bottom end of the dispensing probe  3 . Whether water level covers the dispensing probe  3  or not. The dissolved diluted liquid also does not flow out through the air vents  33  at the top end. As the top end is covered by the inverse U-shaped cap which can trap air, the gaps  34  have air to isolate the diluted liquid. The inlet/outlet  30  at the bottom end is an opening employs pressure difference in the U-shaped pressure trap passage  32 . Because (B-C)&gt;(A-B), experiments show that the dilute liquid which has a greater specific gravity than water does not flow over point B or flows out. In the event of (B-C)&lt;(A-B), the dilute liquid flows over B point and flows out slowly from the dispensing probe  3 . 
     Referring to FIG.  4  and FIG. 6, because the differential gravity of the liquid level between aperture  506  and outlet  505  is higher than threshold Force, the inventor of the present invention designates the threshold Force as Force of breakthrough (Fb) temporarily. The threshold Force (Fb) of the present invention is a lowest gravity force feeding which drives air to flow in a drip tube  504  from aperture to form an air bulb raising upward in the liquid bottle  2  to replace the space, so that the liquid flows from the outlet  505  into the through  510 . When concentrate detergent liquid flows through the outlet  505  into the trough  510 , the liquid level in the trough rises and the liquid stops flowing out when the liquid level reaching the air aperture  506 . In that condition, gravity of the liquid level difference is proximate to or smaller than Fb. Tensile strength of liquid around aperture  506  becomes smaller and air bubbles cannot be generated to allow air to enter into the tube  504 . Based on the principle of liquid partial pressure and gravity force feeding, the flow speed is faster when more liquid contained in the liquid bottle  2 . However, Fb value has no relationship with the amount of liquid contained in the liquid bottle  2 , i.e. the control position for stopping liquid flowing out does not change because of different amount of liquid contained in the liquid bottle  2 . When water enters, the rising water level moves the quantitative float barrel  51  upwards to compress liquid held in the trough  510  such that liquid in the trough flows out of the trough air aperture  506  and opening  511 . The quantitative float barrel  51  continuously rises and reaches the base dock  50  and completely surrounds and seals the entire cylindrical drip tube  504 . The up and down displacement of the quantitative float barrel  51  and the outer diameter of the cylindrical drip tube  504  enable the quantitative float barrel  51  to squeeze and release a constant amount of concentrate liquid in every up and down movement into the dilute buffer chamber  4  for dilution. The dispenser thus constructed therefore forms a completely separated and quantitative dilution system. 
     During flushing, water level drops, and when water level pressure difference outside the dispensing probe  3  is greater than the pressure difference (B-C)−(A-B) in the U-shaped pressure. trap passage  32 , dilute liquid starts flowing out through the inlet/outlet  30  of the dispensing probe  3 . As most of the dilute liquid is stored in the upper section of the dispensing probe  3 , and the inlet/outlet  30  is located in the lower half section of the water tank, after water is flushed about 5-10 seconds, most of the dilute liquid is flushed into the toilet, and only a small amount of the dilute liquid remains in the water tank. 
     Another characteristics of the invention is to use suction force of a sucking disc  6  to mount the dispenser  1  on the inner wall of the water tank in a suspension manner. Referring to FIGS. 1 and 4, the sucking disc  6  is fixedly located on an opening  37  on the right side of the dispensing probe  3 . There is an air vent  38  on the other side for installation use. The anchor disc  7  has a protrusive perimeter with a smooth surface  70 . The anchor disc  7  has another side applying with silicone adhesive or other adhesives for adhering the anchor disc  7  to the inner wall of the water tank at a desired elevation. Then the sucking disc  6  may be mounted to the smooth surface  70  by means of suction force by compressing the sucking disc  6  against the anchor disc  7 . The entire dispenser  1  thus may be hung thereon. Testing with additional weights in various temperatures (4-25 degrees Celsius) shows that, the non-slipping suction force of the sucking disc  6  is about 1200 grams, and the maximum loading weight of the suction force without breaking off is about 1800 grams. Both are far greater than the maximum weight of 200 grams that has been commonly adopted for a regular dispenser  1 . Test for suction time duration capability is done by simulations of adding an extra weight to shorten testing time period. A test was done by hanging a weight of 700 grams to the sucking disc  6  in a static condition. There was no slipping or breaking off occurred after two months have been elapsed. The outcome indicates that the invention can meet requirements of practical applications. General plastic water tanks made by thermosetting usually have smooth inner surfaces, hence the sucking disc  6  can be directly adhered thereon without using the anchor disc  7 . However ceramic water tanks generally have porous inner surfaces, the anchor disc  7  is required to mount the sucking disk  6  to the inner wall of the ceramic water tanks. Installation of the whole dispenser system of the invention by means of the sucking disc  6  and anchor disc  7  is very simple and easy, and may be adopted for any types of toilets. Moreover, the dispenser  1  of the invention may be mounted to any elevation in the water tank and still function properly, even in the condition of being submerged in the water. Nevertheless, in practice, it is still preferably to mount the dispenser  1  to a desired water level to allow water flushing first, then flush the dilute detergent liquid so that some dilute detergent liquid will be retained in the toilet bowl to achieve most effective sanitary results. 
     In another embodiment of the invention for a dispenser  8  (referring to FIG.  8 ), operation principles of the sucking disc  6 , anchor disc  7 , and dispensing probe  3  are same as those of the liquid dispenser  1 . However there is no liquid quantitative device  5 . And the interior construction of the dilute buffer chamber  80  is altered. Referring to FIGS. 9 and 10, the dilute buffer chamber  80  has openings to communicate with and fasten to the dispensing probe  3  through the openings  35  and  36 . In the dilute buffer chamber  80 , there is a partition  800  to separate and form a storage compartment  801  for holding Lavatory cleansing block or jelly. The partition  800  has an opening  802  formed on an upper section. There is a top opening  804  formed on the top end of the dilute buffer chamber  80  and is coupled by a movable lid  81 . Cleansing block or jelly may be dropped into the storage compartment  801  of the dilute buffer chamber  80  through the top opening  804 . There is another partition  803  to channel the cleansing block moving correctly into the storage compartment. Cleansing jelly may be added to a height without exceeding the lower section of the opening  802 . Once cleaners are added through the top opening  804 , the movable lid  81  may be closed to seal the top opening  804 . Feeding water enters through the inlet/outlet  30  of the dispensing probe  3  and rises to the lower opening  35  and enters into the dilute buffer chamber  80 , then flows over the partition  800  to blend with the cleansing material contained in the storage compartment  801 ; and slowly dilute and disperse into the dispenser  8 . By means of up and down of water level, irregular amount of cleansing materials may be flushed into the toilet bowl. 
     Industrial Applicability 
     The quantitative liquid dispenser of the invention may be used to dispense liquids from a reservoir or bottle, and in particular may be used in the toilet tank to dispense quantitative cleansing liquids into a toilet bowl.

Summary:
A liquid dispenser employs passive driving force resulting from water level variations in the water tank of a toilet to dispense a quantitative amount of liquid into toilet bowl of each Flush is disclosed. A sanitary concentrate detergent of a selected formula is filled and sealed in a bottle and mounted to a float quantitative dispensing device in a dilute buffer chamber. Through up and down movement of a float quantitative barrel, a constant amount of concentrate liquid is squeezed and isolated into the dilute buffer chamber for dilution. The whole dispenser apparatus is hung inside. the toilet tank at a desired elevation by means of suction force of a sucking disc. A dispensing probe is provided which has an inlet/outlet submerged in the low portion of the toilet tank. When toilet is flushed, most diluted detergent in the dispenser is flushed into the toilet bowl for cleaning use, and only a small amount of the diluted detergent is retained in the toilet tank. The liquid dispenser uses the principle of liquid partial pressure difference and gravity force feeding. The precision of sampling volume is not changed along with the residual liquid in the liquid bottle.