WO2004032981A1

WO2004032981A1 - Apparatus for automatically supplying water in dental water tank

Info

Publication number: WO2004032981A1
Application number: PCT/KR2003/002066
Authority: WO
Inventors: Cha-Hyoung Koo
Original assignee: Cha-Hyoung Koo
Priority date: 2002-10-08
Filing date: 2003-10-07
Publication date: 2004-04-22
Also published as: TWI236892B; TW200405805A; AU2003267844A1

Abstract

There is disclosed an apparatus for automatically supplying water in dental water tank with which water is purified, stored at water tank and sterilized to be continuously supplied to dental equipment. An automatic water supply apparatus for dental water tank according to an embodiment of the present invention includes a water-purifying part to purify original water; a water tank where the purified water is stored; a pump installed between the water-purifying part and the water tank to pump the purified water; a compressed air supplier to supply compressed air to the water tank; a sterilizer installed within the water tank to sterilize the purified water; a water level controller installed within the water tank to sense the level of water stored at the water tank and control the pump when the level of water is higher than a designated level, thereby maintaining the level of water within the water tank at a fixed level; an auxiliary water tank to store water for responding to the case that there occurs water supply cut; and an auxiliary pump to be driven upon water supply cut or the breakdown of the pump in order to supply any one among the water stored within the auxiliary tank or the original water, to the water tank.

Description

APPARATUS FOR AUTOMATICALLY SUPPLYING WATER IN DENTAL WATER TANK

Technical field

This application claims the benefit of the Korean Patent Applications Nos. P2002-61234 filed on October 8, 2002 and P2003-68130 filed on October 1, 2003, which are hereby incorporated by reference.

Background Art

The present invention relates to an apparatus for automatically supplying water in dental water tank, and more particularly to an apparatus for automatically supplying water in dental water tank with which water is purified, stored at water tank and sterilized to be continuously supplied to dental equipment. Further, the invention relates to an apparatus for automatically supplying water in dental water tank with which water can be automatically supplied to the water tank even when there is breakdown or failure in water supply, and that is capable of preventing a pipe from being frozen to burst and the water from leaking and biofilm from being formed so that hot water is effectively supplied to pipes and a dental unit chair.

Generally, the water supplied to a dental equipment is used to cool down the heat generated at a hand piece of a unit chair and to get rid of powder remnants or is used when brushing teeth. The pressure of the water supplied to dental equipment should be evenly maintained at 1.8~2.5kgf/cm². In prior art, in order to supply water to the dental equipment, a person in charge opens the lid of water tank called Kola tank to fill the tank with water to a certain level, and then close the lid to seal up. After that, compressed air is injected into the upper part of the water tank. And a valve installed at the water supply pipe of the water thank is turned open. If the person in charge opens the valve at the water supply pipe, the water inside the water tank is supplied to the dental equipment by the pressure of compressed air, and if the water within the storage tank runs out, the person in charge cuts off the compressed air inflow and exhausts the compressed air within the water tank. And then the process of opening the lid of the water tank and filling the water tank with water should be repeated. In this way, the process of filling water in the water tank repeats opening and closing the lid, supplying water, supplying compressed air and opening and closing valve, so it causes a lot of inconvenience to a user and the compressed air should be wasted whenever water is filled into the water tank. If unpurified water s supplied to dental equipment such as hand piece, sealer and etc, dental equipment can be damaged or malfunctioned, e.g., a minute tube is clogged by impurities included in the water, so that its lifespan can be shortened as much.

Further, the prior art dental water supply apparatus does not have a air-cleaning device, thus when opening the lid of the water tank, the water within the water tank and the water supplied to the dental equipment may be contaminated due to the tiny particles, bacteria, Virus and etc mixed with the air flowing into the water tank. Further, the prior art dental water supply apparatus is frozen to burst when the external temperature decreases, and there is no way to correspond to leakage or water supply cut when the person in charge is absent, e.g., other than consultation hours.

Further the prior art dental water supply apparatus has no sterilizing device, thus when performing dental examination, the hand piece, sealer and etc are made to contact to the contaminated teeth or infected part within the mouth of patient. Thus, various bacteria existing in the infected part can form a biofilm in the hose and water tank connected to the dental equipment, e.g., hand piece, sealer and etc, thus it can propagate itself and the infected bacteria can cause secondary infection of other patients.

Disclosure of Invention

Accordingly, it is an object of the present invention to provide an apparatus for automatically supplying water in dental water tank with which water is purified, stored at water tank and sterilized to be continuously supplied to dental equipment.

It is another object of the present invention to provide an apparatus for automatically supplying water in dental water tank with which water can be automatically supplied to the water tank even when there is breakdown or failure in water supply, and that is capable of preventing a pipe from being frozen to burst and the water from leaking and biofilm from being formed so that hot water is effectively supplied to pipes and a dental unit chair in winter.

In order to achieve these and other objects of the invention, an automatic water supply apparatus for dental water tank according to an aspect of the present invention includes a water-purifying part to purify original water; a water tank where the purified water is stored; a pump installed between the water-purifying part and the water tank to pump the purified water; a compressed air supplier to supply compressed air to the water tank; a sterilizer installed within the water tank to sterilize the purified water; a water level controller installed within the water tank to sense the level of water stored at the water tank and control the pump when the level of water is higher than a designated level, thereby maintaining the level of water within the water tank at a fixed level; an auxiliary water tank to store water for responding to the case that there occurs water supply cut; and an auxiliary pump to be driven upon water supply cut or the breakdown of the pump in order to supply any one among the water stored within the auxiliary tank or the original water, to the water tank.

The automatic water supply apparatus for dental water tank further includes a plurality of water level sensing sensors installed at the water tank in correspondence to upper limit water level, middle water level and lower limit water level of the water stored at the water tank to sense the level of the water stored at the water tank; a temperature sensor installed within the water tank to sense the temperature of the water stored at the water tank; and a heater installed within the water tank to boil the water stored the water tank.

The automatic water supply apparatus for dental water tank further includes a controller to control the auxiliary pump in response to a signal from the water level sensing sensor and to control the heater in response to a signal from the temperature sensor.

Herein, the controller drives the auxiliary pump when the pump is broken down.

The automatic water supply apparatus for dental water tank further includes a water discharging tube to supply the water stored at the water tank to a dental unit; a water returning tube installed between the water discharging tube and the water tank to return the water from the water discharging tube to the water tank; and a circulation pump to circulate sterilizing water within the water tank between the water discharging tube and the water tank.

In order to achieve these and other objects of the invention, an automatic water supply apparatus for dental water tank according to another aspect of the present invention includes a water tank where purified and sterilized water is stored and which discharges the water at a fixed pressure; a water discharging tube to supply the purified and sterilized water from the water tank to at least one unit chair including utmost end medical equipment; a chemical tank storing chemicals for sterilization; a chemical supply tube connected between the chemical tank and the water discharging tube to supply the sterilization chemical to the water discharging tube; and a valve installed at the chemical supply tube to open and close a supply route of the chemical .

The automatic water supply apparatus for dental water tank further includes an auxiliary water tank storing water in case of water supply cut; an auxiliary water supply tube connected between the water tank and the auxiliary water tank to supply the water of the auxiliary water tank to the water tank; and a water supply cut responding valve installed at the auxiliary water supply tube to open and close supply route through which the water of the auxiliary water tank flows.

The automatic water supply apparatus for dental water tank further includes a water returning tube installed between the water discharging tube and the water tank to return the water from the water discharging tube to the water tank; and a water returning value installed at the water returning tube to intercept a water supply route of the water returning tube while the chemical is supplied.

Herein, the chemical includes at least one of sodium hypochloπte NaOCl, Chloramme, Elemental Chlorine, Chlorheidine, H₂0₂, Iodine composition .

The automatic water supply apparatus for dental water tank further includes a pump connected to any one of the water discharging tube or the water returning tube to circulate the water between the water discharging tube and the water returning tube; and a three-way valve connected between the water returning tube, the water tank and the a waste water disposer.

Brief Description of Drawings

These and other objects of the invention will be apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings, in which:

FIG. 1 is a drawing representing an automatic water supply apparatus for a dental water tank according to a first embodiment of the present invention;

FIG. 2 is a drawing representing a compressed air supply part in order to supply compressed air to the automatic water supply apparatus for the dental water tank shown in FIG. 1;

FIG. 3 is a drawing representing a connection relation between a water discharging tube and a water returning tube shown in FIG. 1;

FIG. 4 is a drawing representing an automatic water supply apparatus for a dental water tank according to a second embodiment of the present invention;

FIG. 5 is a drawing representing a connection relation between a water discharging tube and a water returning tube shown in FIG. ; and FIG. 6A and 6B are drawings representing motions of a ball top shown in FIG. 1 and 4.

Best Mode for Carrying out the Invention

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

With reference to FIGs .1 to 3, embodiments of the present invention will be explained as follows.

Referring to FIGs. 1 to 3, an automatic water supply apparatus for dental water tank according to the present invention includes a water-purifying part 2 to purify original water; a water tank 10 connected to a dental unit chair through a water discharging tube 19 and a water returning tube 12; a pump 3A and an auxiliary pump 3B for supplying the purified water to the water tank 10 at a certain pressure; a ball top 34 floating by buoyancy on the water stored at the water tank 10; a first water supply tube 32 of which a water supply hole is intercepted by the ball top 34 when water stored with the water tank 10 reaches a designated level of water; a second water supply tube 33 arranged between the water-purifying part 2 and water cooler/heater 17 for dirking water; a waste water tube 31 arranged between the water-purifying part 2 and a waste water disposer 9; an ozone lamp 13, a temperature sensor 15, a heater 16 arranged inside the water tank 10; a compressed air supplier 40 to supply the purified, compressed air to the inside of the water tank 10; a controlling part 60 to provide an interface with a person in charge as well as control solenoid valves 1A, IB, 1C, ID, three way valves 5A, 5B, the heater 16 and pumps 3A, 3B, which are arranged at tubes 31, 32, 33, 37 in which water flows.

The original water, which is tap water or subterranean water, is supplied to the water-purifying part 2 through the original water tube 37 and the first solenoid valve 1A.

The water tank 10 is made of stainless steel SUS. The water flowing in from the pumps 3A and 3B is controlled by a water level controlling mean including the ball top 34 and the controller 64, thus the water stored within the water tank 10 always remains at a fixed level of water. Therefore, water is supplied to the water tank 10 without opening and closing a lid, thus there occurs no secondary infection of the water tank 10, which is infected by the contaminated air when supplying water in the prior art. The auxiliary tank 50 has water stored to correspond when there is failure of water supply and is made of stainless steel SUS.

The controlling part 60 includes a controller 64 , a memory 61 connected to the controller 64, a display device 62 and an input/operational panel 63. Further detail will be described later.

The water purifying part 2playsaroleof removing various impurities, such as rust, floating material or chemical contamination material, heavy material, ion, bacteria and so on, contained in the original water supplied from the original water tube 37. For this, the water-purifying part 2 includes a pre-sediment filter 21 arranged between the first solenoid valve 1A and the pump 3A; a pre-carbon filter 22, a post-carbon filter 23 and a post-sediment filter 24 disposed in series between the auxiliary pump 3B and the two three-way valve 5B; a reverse osmotic pressure filter 7 arranged between the two three-way way valve 5B and the water supply tubes 32 and 33; and a TOR filter 8 arranged between the reverse osmotic pressure filter 7 and the water cooler/heater 17 for drinking water.

The sediment filters 21 and 24 includes non-woven fabric or a filter bed, and removes the various impurities, such as rust and floating material, contained in the original water. The carbon filters 22 and 23 remove chemical contamination material . The reverse osmotic pressure filter 7 removes heavy metal and bacteria and ion material in use of a membrane intercepting heavy metal, bacteria and ion material, which are bigger than water molecule, while passing water H₂0 through. The TOR filter 8 removes the unpleasant taste and smell of water and supplies the purified water to the water cooler/heater for drinking water.

The pump 3A is driven by electric power supplied from an adaptor 4A under the control of the controller 64, so as to supply the water purified by the water purifying part 2 to the water tank 10 at a designated pressure. The pump 3A smoothly supplies the original water to the water-purifying part 2 and the purified water is filled into the water tank 10. For example, if the pressure of the original water is low, the original water is pressurized at a pressure higher than a designated pressure by the pump 3A, thus the water is smoothly purified by the water-purifying part 2. The pump 3A supplies the purified water to the water tank 10 at a certain pressure until it is stopped by the controller 64.

The compressed air supplier 40 includes an compressor 25, an air cleaner 26 and a pressure controller 27 connected in series as in FIG. 2. The compressor 25 generates compressed air and the air cleaner 26 includes an air cleaning filter having minute membranes such as non-woven fabric, filtering device and so on to remove various impurities and powdered dust contained in the compressed air compressed by the compressor 25. The pressure controller 27, as a regulator, controls the pressure of the compressed air cleaned by the air cleaner 26. The pressure of the compressed air cleaned by the air cleaner 26 is 8~6kgf/cm², but the pressure of the compressed air controlledbythe pressure controller 27 remains at 1.8~2.5kgf/cm². The compressed air with a designated air pressure keeps the water stored within the water tank 10 pressurized at a fixed pressure. As a result, the compressed air generated from the compressed air supplier 40 flows into the water tank 10, thus the water stored within the water tank 10 is supplied to the dental unit chair at a fixed pressure by the compressed air. The water supplied to the dental unit chair is again supplied to the hand piece, a mouth cleaning table and a sealer installed at the dental unit chair.

Further, the pressure controller 27 senses the pressure of a first water supply tube 32 and stops the pump 3A for no more water to be flow into the water tank 10 if the pressure of the first water supply tube 32 reaches a designated pressure.

The ball top 34 has air injected into the inside thereof in order to generate buoyancy and floats on the water surface within the water tank 10. The ball top 34 is connected to one end of a lever of which the other end is connected by hinge as shown in FIGs. 6A and 6B and moves up and down along the water level within the water tank, thereby pushing up or down a water supply hole plug 32B. The water supply hole plug 32B opens and closes the water supply hole 32A in connection with the up and down movement of the ball top 34. That is, the ball top 34 blocks up the water supply hole 32A of the first water supply tube 32 when the water level within the water tank 10 reaches a designated level. If the water supply hole 32A of the first water supply tube 32 is blocked by the ball top 34 in this way, the pressure within the first water supply tube 32 increases.

The auxiliary pump 3B is driven to supply the original water to the water purifying part 2 and the water tank 10 at a designated pressure when the pump 3A is broken down under the control of the controller 64. If the pump 3A is out of order in other reason than water supply cut, the level of water stored within the water tank 10 abnormally becomes low. In this way, when the level of water stored within the water tank 10 is sensed to be below lower limit in other reason than water supply cut, the controller 64 judges the pump 3A being broken so as to drive the auxiliary pump 3B.

To sense the level of water within the water tank 10, water level sensing sensors 18A, 18B, 18C are installed at the locations corresponding to upper limit water level, middle water level and lower limit water level, in the water tank 10. Each of the water level sensing sensors 18A, 18B, 18C generates water level sensing signals Sh. The controller 64 judges that water supply to the water tank 10 cannot be made because of the breakdown of the pump 3A or blockage of the reverse osmotic pressure filter 7 when the lower limit lower level sensing signal among the water level sensing signals Sh is inputted for more than a designated time, thereby starting the auxiliary pump 3B and making the two three-way valve 5B work to fill the water tank 10 within a fast time period through a UF membrane filter 70, which has big pores between the post-sediment filter 24 and the first water supply tube 32.

On the other hand, the controller 64 controls the first and second three-way valve 5A and 5B to switch the route of water so that the water stored at the auxiliary water tank 50 is supplied to the water tank 10. At this moment, the water stored at the auxiliary water tank50 ispurifiedatthe water-purifying part 2 through the auxiliary water supply tube 35, a fourth solenoid value ID, the first three-way value 5A, the auxiliary pump 3B, and then supplied the water tank 10 through the second three-way value 5B and the third water supply tube 36.

The ozone lamp 13 installed within the water tank 15 convert the water stored with the water tank 10 into ozone water to sterilize the water stored with the water tank 10. The water converted into the ozone water by the ozone lamp 13 has sterilizing power and is supplied to the water discharging tube 12 through the outgoing water tube 11. The outgoing water tube 11 is extended to almost the bottom of the water tank 10 so that water can be supplied to the dental unit chair even when the level of water is low. The water converted into the ozone water by the ozone lamp 13, i.e., sterilized water, is supplied to the dental unit chair through the water discharging tube 19 and supplied to the water tank 10 through the water returning tube 12 as shown in FIG. 3, thereby maintaining the sterilizing power within pipes by continuously circulating between the water tank 10 and the unit chair. For example, in the prior art if water is not discharged from the unit chair, the water within the water discharging tube installed between the water tank and the unit chair is congested, thus the water loses the sterilizing power even though it is sterilized. In this case, tubes for hoses arranged between the water tank 10 and the unit chair are infected and such infection causes the secondary infection of the water tank or the mouth of patient. On the contrary, the automatic water supply apparatus for dental water tank according to the present invention makes the water stored within the water tank 10 converted into the ozone water to get the sterilizing power and the ozone water sterilized to keep the sterilizing power, thereby always sterilizing the water discharging tube installed between the water tank and the dental unit chair. The ozone lamp 13 is discharged by the electric power from the adaptor 14. In stead of the ozone lamp 13, an ozone generator can be used. The ozone generator electrolyzes water and converts oxygen into ozone water in use of electric discharge. The ozone generator is more effective when the dissolve oxygen of the water stored within the water tank 10.

In case of the external temperature being low, i.e., winter and so on, the automatic water supply apparatus for dental water tank according to the present invention circulates water boiled within the water tank 10, thereby preventing water from being congested within the pipes and effectively supplying hot water to the dental unit chair or dental equipment.

In order to prevent water leakage from occurring in a time period other than a consultation hour, when person in charge is absent, the controller 40 stops the pumps 3A, 3B and the compressed air supplier 40 during the time period other than the consultation hour registered by the person in charge. In this case, the ozone lamp 13 continues to be driven to sterilize the water stored within the water tank 10. The consultation time information inputted through an input/operational panel 63 is stored at the memory 61.

The temperature sensor 15 senses the temperature of the water stored at the water tank 10 to supply temperature sensing signals St, which indicates the temperature of the water, to the controller 64. In response to the temperature sensing signal St, the controller 64 drives the heater 16 to prevent it from being frozen to burst when the temperature of the water stored at the water tank 10 remains for a designate time at a designated temperature, e.g., 5 ^°C and below. Then, the heater 16 increases the temperature within the water tank 10 under control of the controller 64, thereby preventing it from being frozen to burst.

The input/operational panel 63 has the on/off key of power, a pressure gauge indicating the pressure of the water tank, a keyboard and so on installed on it so that the person in charge is allowed to control the automatic water supply apparatus for dental water tank and to watch and control the pressure of water. Further, the person in charge can enter and renew the information such as consultation hour and so on through the input/operational panel 63.

The display device 62 displays the information inputted from the controller 64 to allow the person in charge to know the operational state of the automatic water supply apparatus for dental water tank.

The waste water disposer 9 plays role of discharging waste water supplied from the reverse osmotic pressure filter 7 in use of a film where minute holes are formed. The third solenoid valve 1C installed at both ends of the waste water disposer 9 bypasses the waste water at a rapid speed without having it go through the waste water disposer 9, under control of the controller 64. Thus it makes the remnants stuck to the wall of reverse osmotic pressure filter 7, which is an ultra-minute film, due to the waste water disposer 9.

The fourth solenoid valve ID installed between the first three-way valve 5A and the auxiliary water tank 50 is only open when there is water supply cut under control of the controller 64.

FIGs. 4 and 5 represent the automatic water supply apparatus for dental water tank according to another embodiment of the present invention. In FIGs.4 and 5, as to the same components as the foregoing embodiment, the same reference numerals are to be put andmore detailed description thereof will be omitted. And in this embodiment, the compressed air supplier 40 is substantially similar to that of the foregoing embodiment, thus the drawings and further description thereof will be omitted.

Referring to FIGs. 4 and 5, the automatic water supply apparatus for dental water tank according to the embodiment of the present invention includes an auxiliary water tank 51 directly connected to the water tank 10; a pump 3C for pumping the water running inside the water discharging tube 12 and the water returning tube 19; and a chemical tank 12 for supplying chemical to the water discharging tube 12.

The auxiliary water tank 51 stores water in case there is water supply cut and is made of stainless steel SUS. A solenoid valve IE connected to the auxiliary water tank 51 can be electrically controlled by the controller 64, but can be replaced with a manual valve .

Further, the automatic water supply apparatus for dental water tank according to the present invention includes a chemical supply tube 53 connected between a chemical tank 52 and the water discharging tube 12, a solenoid valve 55 connected to the chemical supply tube 53, and a three-way valve 54 installed at the water returning tube 19.

The tubes or hoses within the end medical equipment 71 to 7K such as the dental unit chair 101 to 10K, the hand piece, the mouth cleaning table, the sealer and etc can be sterilized with the water having sterilizing power and chemical mixed with the water m the overall sterilizing mode. In this overall sterilizing mode, the three-way valve 54 connected to the water returning tube 19 is connected to the waste water disposer, which deals with the water returning tube 19 and waste water, under control of the controller 64 for a fixed time period. And the three-way valve 54 cuts off the relation between the water returning tube 19 and the waste water disposer and opens the water supply route between the water returning tube 19 and the water tank 10 in a normal driving state and not m the overall sterilizing mode.

The solenoid valve 55 connected to the chemical supply tube 53 opens the chemical supply route between the chemical tank 52 and the water discharging tubel2ιnthe overall sterilizingmode . And the solenoid valve 55 cuts off the chemical supply route between the chemical tank 52 and the water discharging tube 12 and opens the water supply route between the water discharging tube 12 and the water tank 10 in the normal driving state and not in the overall sterilizing mode. The chemical stored inside the chemical tank 52 is supplied to the water discharging tube 12 in a piston method while it's having in the form of liquid or powder. The chemical includes at least one of sodium hypochlorite NaOCl, Chloramine, Elemental Chlorine, Chlorheidine, H₂o₂ and Iodine Composition.

The pump 3C is connected to the water discharging tube 12 or the water returning tube 19 to circulate water between the water discharging tube 12 and the water returning tube 19, or to pump the water sterilizing the water discharging tube 12 in the overall sterilizing mode toward the waste water disposer.

It is desirable that the water discharging hole of the utmost end medical equipment 71 to 7K installed at each dental unit chair 101 to 10K in the overall sterilizing mode . This is because the chemical is mixed and the water with the sterilizing power by ozone can sterilize the water discharging hole of the utmost end medical equipment 71 to 7K only when the water discharging hole of the utmost end medical equipment 71 to 7K should be open.

The operational time of the overall sterilizing mode is pre-set at the timing controller 64. The solenoid valve 54 connected to the water returning tube 19 and the solenoid valve 55 connected to the chemical supply tube 53 can be replaced with manual valves. In this case, the person in charge closes the manual valve connected to the water returning tube 19 and opens the manual valve connected to the chemical supply tube 53 when the whole sterilization 55 is judged to be necessary. As described above, the automatic water supply apparatus for dental water tank according to the present invention automatically supplies the original water supplied from the water supply source through the water-purifying part to the water tank at a fixed pressure. And it supplies the ozone water generated by sterilizing the water stored at the water tank, to the dental equipment at a fixed pressure . As a result, since there is no need to pour water into the water tank manually, the automatic water supply device for dental water tank according to the present invention can minimize the inconvenience of the maintainer upon supplying water and prevent the water stored at the water tank from being infected, further it can prevent the secondary infection by the tube or hose by way of circulating the water with sterilizing power. And it can reduce the pain of patient when cold water is applied to the chilled teeth of the patient by supplying hot water effectively when the external temperature is low, e.g., in winter. Further, the automatic water supply apparatus for dental water tank according to the present invention normally supplies water to the water tank even when it is broken or there is water supply cut in use of the auxiliary water tank and the auxiliary pump, and senses temperature and boiling the water within the water tank according to the sensed temperature to prevent it from being frozen to burst and stopping the pump and the compressed air supply when no person in charge is absent, thus preventing the leakage, which can be generated when no person in charge is around.

Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather that various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.

Claims

1. An automatic water supply apparatus for dental water tank, comprising: a water-purifying part to purify original water; a water tank where the purified water is stored; a pump installed between the water-purifying part and the water tank to pump the purified water; a compressed air supplier to supply compressed air to the water tank; a sterilizer installed within the water tank to sterilize the purified water; a water level controller installed within the water tank to sense the level of water stored at the water tank and control the pump when the level of water is higher than a designated level, thereby maintaining the level of water within the water tank at a fixed level; an auxiliary water tank to store water for responding to the case that there occurs water supply cut; and an auxiliary pump to be driven upon water supply cut or the breakdown of the pump in order to supply any one among the water stored within the auxiliary tank or the original water, to the water tank.

2. The automatic water supply apparatus for dental water tank according to claim 1, further comprising: a plurality of water level sensing sensors installed at the water tank in correspondence to upper limit water level, middle water level and lower limit water level of the water stored at the water tank to sense the level of the water stored at the water tank; a temperature sensor installed within the water tank to sense the temperature of the water stored at the water tank; and a heater installed within the water tank to boil the water stored the water tank.

3. The automatic water supply apparatus for dental water tank according to claim 2, further comprising: a controller to control the auxiliary pump in response to a signal from the water level sensing sensor and to control the heater in response to a signal from the temperature sensor.

. The automatic water supply apparatus for dental water tank according to claim 3, wherein the controller drives the auxiliary pump when the pump is broken down.

5. The automatic water supply apparatus for dental water tank according to claim 1, further comprising: a water discharging tube to supply the water stored at the water tank to a dental unit; a water returning tube installed between the water discharging tube and the water tank to return the water from the water discharging tube to the water tank; and a circulation pump to circulate sterilizing water within the water tank between the water discharging tube and the water tank.

6. An automatic water supply apparatus for dental water tank, comprising: a water tank where purified and sterilized water is stored and which discharges the water at a fixed pressure; a water discharging tube to supply the purified and sterilized water from the water tank to at least one unit chair including utmost end medical equipment; a chemical tank storing chemicals for sterilization; a chemical supply tube connected between the chemical tank and the water discharging tube to supply the sterilization chemical to the water discharging tube; and a valve installed at the chemical supply tube to open and close a supply route of the chemical.

7. The automatic water supply apparatus for dental water tank according to claim 6, further comprising: an auxiliary water tank storing water in case of water supply cut; an auxiliary water supply tube connected between the water tank and the auxiliary water tank to supply the water of the auxiliary water tank to the water tank; and a water supply cut responding valve installed at the auxiliary water supply tube to open and close supply route through which the water of the auxiliary water tank flows.

8. The automatic water supply apparatus for dental water tank according to claim 6, further comprising: a water returning tube installed between the water discharging tube and the water tank to return the water from the water discharging tube to the water tank; and a water returning value installed at the water returning tube to intercept a water supply route of the water returning tube while the chemical is supplied.

9. The automatic water supply apparatus for dental water tank according to claim 6, further comprising: a plurality of water level sensing sensors installed at the water tank in correspondence to upper limit water level, middle water level and lower limit water level of the water stored at the water tank to sense the level of the water stored at the water tank; a temperature sensor installed within the water tank to sense the temperature of the water stored at the water tank; and a heater installed within the water tank to boil the water stored the water tank.

10. The automatic water supply apparatus for dental water tank according to claim 6, wherein the chemical includes at least one of sodium hypochlorite NaOCl, Chloramine, Elemental Chlorine, Chlorheidine, H₂0₂, Iodine composition.

11. The automatic water supply apparatus for dental water tank according to claim 8, further comprising: a pump connected to any one of the water discharging tube or the water returning tube to circulate the water between the water discharging tube and the water returning tube; and a three-way valve connected between the water returning tube, the water tank and the a waste water disposer.