Water storage tank and household water purifier having same

A water storage tank is provided with a water storage bag for storing finished water and a space for accommodating squeezed water outside of the water storage bag. The water storage tank enables a rapid introduction of squeezed water by having a flow guiding groove connected in communication with the space for accommodating squeezed water. A hollow tube extending into the water storage bag is arranged to prevent distortion of the water storage bag, so as to completely squeeze the finished water out of the bag. A cylindrical middle part and two ellipsoidal or hemispherical ends of the water storage tank can improve the stress bearing performance of the water storage tank. A household water purifier using the water storage tank is also described.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. 371 of PCT/US2018/013735, filed Jan. 15, 2018, which claims the benefit of Chinese Patent Application No. 201710033352.0, filed Jan. 17, 2017, the disclosures of which are incorporated by reference in their entirety herein.

TECHNICAL FIELD

The present invention belongs to the technical field of liquid purification, and more particularly to a water storage tank and a household water purifier including the same.

BACKGROUND

With more emphasis users are putting onto the drinking water safety, having household water purifiers installed is increasingly popular.

Due to the difference in water source conditions, the supplied water quality of cities in different areas are different. For example, the average water hardness in the northern China is higher than that in the central and eastern China, which in turn is higher than that in the southern China. In general, the phenomenon of having scale deposits formed after heating drinking water is relatively common in areas with high water hardness. In order to solve the problem of scale deposits, a majority of water purifier manufacturers use a filtering technique with a reverse osmosis membrane to manufacture a reverse osmosis water purifier.

A small reverse osmosis water purifier provides a low pure water flow from the membrane element (50 to 200 gallons/day); and a direct use from the small water purifier cannot meet the user's requirement for water use. A water storage tank is therefore used to store pure water; and pure water flowing out of the tap is actually from the water storage tank.

The water storage tank has two chambers partitioned with an elastic separator therein, where one chamber is configured to storage pure water and the other chamber contains compressed air at a certain pressure; when a user turns on the tap, pure water in the chamber storing purified water can then be squeezed out of the tap.

When water in the water storage tank is full, the volume of compressed air is at its minimum and the pressure is at its maximum; and the flow rate of output water is at its maximum the second the user turns on the tap. However, when pure water in the water storage tank is reduced and the volume of compressed air increases, the pressure becomes increasingly lower and the flow rate of water output from the tap also becomes increasingly lower, leading to a poor user experience in the process of continuously using of the water tank and a longer user waiting time.

In order to solve the above problem, U.S. Pat. No. 7,726,511 reveals a water storage tank for a reverse osmosis filter system. A bag within the water storage tank divides the inner chamber within the tank into two chambers, wherein one chamber is a finished pure water chamber and the other is a squeezed water chamber in place of a compressed air chamber. When a user needs water, water at pressure is introduced into the water storage tank; and pure water is squeezed out of the tap because the bag is squeezed. Because of the stable water pressure of the squeezed water, a stable squeezed flow of finished water can be obtained. Although the invention solves the problem of unstable flow resulting from the reduction in the air pressure within a conventional water storage tank, the tank of the invention has a spherical shape, which is unfavorable to the integration design of small reverse osmosis water purifiers; at the same time, in the invention, some squeezed water remains within the tank when the finished water bag is filled up with water; and the squeezed water occupies the space of the tank; furthermore, in the process of squeezing the finished water, the bag may be distorted and thus the finished water cannot be squeezed out completely.

SUMMARY

In line of the above, the water storage tanks employed in the existing household reverse osmosis purifiers suffer from defects in the design. Therefore, the present invention is intended to provide an alternative water storage tank to solve the above problem.

According to one aspect of the present invention, a water storage tank is provided, comprising: a shell with an inner wall forming an inner chamber of the water storage tank, the water storage tank being provided with a water storage bag assembly, wherein the shell comprises a first channel connecting finished water into the water storage bag assembly and a second channel connecting squeezed water to a squeezed-water space between the water storage bag assembly and the inner wall of the shell, and the water storage bag assembly has an external surface area greater than or equal to a surface area of the inner wall of the shell; and a top cap, disposed at a top of the shell and the top cap having an inner wall forming a hollow top cap chamber, wherein the top cap comprises a third channel connected in communication with the first channel of the shell and a fourth channel connected in communication with the second channel of the shell, and both the third and the fourth channels are connected in communication with the top cap chamber, wherein the second channel of the shell is connected in communication with a flow guiding groove disposed on the shell surface and connected in communication with the squeezed-water space.

According to another aspect of the present invention, a household water purifier comprising the water storage tank as described above is provided.

The water storage tank according to the present invention is suitable for use in filter equipment, and particularly in a pure water system and a household water purifier.

DETAILED DESCRIPTION

In order to allow a person of skill in the art to better comprehend technical solutions of the present invention, the present invention is further described in detail below in combination with the accompanying drawings and particular embodiments.

As shown inFIGS. 1 and 2, the water storage tank of this example is comprised of a shell4000of the water storage tank, a detachable top cap5000, a water storage bag assembly3000, and O-rings5100and5200. The shell4000of the water storage tank has a cylindrical shape and is made of shell4100welded with shell4200or may be made by blow molding as a whole. The shell4000of the water storage tank may be made of high-molecular plastic or metal.

As shown inFIG. 2, the water storage tank is provided, near one end of the top cap, with two channels respectively connecting to finished water100and squeezed water200.

FIG. 3is a schematic view of a vertical cross section of a cylindrical shell and a top cap area of the water storage tank as shown inFIG. 1, wherein an inner chamber of the water storage tank is shown. As shown inFIG. 3, the inner chamber of the water storage tank comprises a water storage chamber400, a top cap chamber500, an upper chamber430, and a lower chamber440. The water storage chamber400has a cylindrical shape, and the upper chamber430and the lower chamber440have either an ellipsoidal or hemispherical shape. The top cap chamber500is connected in communication with the water storage chamber400through the upper chamber430. The ellipsoidal or hemispherical design of the upper chamber430and the lower chamber440can disperse the stress resulting from water pressure borne by both ends of the inner chamber of the water storage tank, thereby improving the stress bearing performance of the water storage tank.

FIG. 4is a schematic view of a vertical cross section of a top cap and an adjacent area thereof of the water storage tank as shown inFIG. 1. As shown inFIG. 4, the outside of the upper chamber430of the shell4000of the water storage tank is provided with a flange4500; the flange4500is provided on the external circumference thereof with an external thread4510, a groove4600, and an O-ring seal4300. The O-ring seal4300is mounted within the groove4600of the flange4500; and the flange groove4600is located between an outside edge of the flange4500and the external thread4510; and the flange4500is coaxial with the cylinder of the water storage tank. The flange4500has two channels410and420therein, wherein the channel410is located in the central area of the flange chamber, and the channel420is distributed around the outside of the channel410.

As shown inFIG. 4, the top cap5000has a combined cylindrical shape in a hollow form, and the hollow chamber is identified by500. One end of the combined cylinder of the top cap5000adjacent to the upper chamber430is5500; and the inner chamber thereof is provided with an internal thread5510and a smooth cylindrical surface5600. The internal thread5510of the top cap5000and the external thread4510of the shell4000of the water storage tank have the same specification and match each other so as to enable mutual engagement and disengagement therebetween through relative rotation and movement, thereby facilitating fixation and disassembly of the top cap5000. When the internal thread5510matches the external thread4510in a predetermined position, the ring seal4300is completely fixed by the chamber formed with the above flange groove4600and the cylindrical surface5600of the top cap, thereby sealing the top cap chamber500at the end face5500.

Please still refer toFIG. 4. The other end5700of the top cap5000away from the upper chamber430is provided with two channels510and520, wherein510is a finished water channel disposed in the central position of the top cap;520is a squeezed-water channel disposed in an external circumference area of the end face5700; and both the two channels are connected in communication with the top cap chamber500. An O-ring seal5400is disposed at the round inner side of the channel510and is configured to partition finished water100from squeezed water within the chamber500; and O-ring seals5100and5200are disposed on the external circumference of the channel520, wherein the O-ring seal5100is configured to partition finished water100from squeezed water200outside the tank body of the water storage tank; and the O-ring seal5200is configured to prevent squeezed water200from coming in contact with the outside world of the tank body of the water storage tank.

As shown inFIG. 4, both flange channels410and420can be connected in communication with the chamber400and the top cap chamber500of the water storage tank, wherein410is a finished water channel and420is a squeezed-water channel. As shown inFIG. 5, channel420is a group of round through holes distributed at the periphery of the channel410around the axial line of the chamber400of the water storage tank and connected in communication with the chamber400of the water storage tank through a surface of the upper chamber430. Specifically, each round hole of the channel420is provided with a flow guiding groove4200on a surface contacting the upper chamber430. As shown inFIG. 5, the flow guiding groove4200is distributed at the surface of the upper chamber430around the axial line of the chamber400of the water storage tank.

FIG. 6a schematic view of a vertical cross section of the water storage bag assembly3000. As shown inFIG. 6, the combination3000comprises a film water storage bag3100and a joint3200. The water storage bag3100can be made of a plastic or rubber film and is combined with the joint3200through a process such as adhesion or welding; and a water storage bag chamber300is formed and configured to store finished water100. The joint3200is a hard member made of high-molecular plastic and is connected to the water storage bag3100to mount and seal the water storage bag3100to the top cap5000and the shell4000. In this particular embodiment, the joint3200is hollow and is thus configured to provide a channel for finished water to flow in and out of water storage bag3100. In another aspect, the water storage bag300is connected in communication with outer finished water100(e.g., finished pure water that has been treated by a reverse osmosis filtering system) through a central tube3300of the joint and the water inlet and outlet3400of the joint; and the inlet and outlet channel310for the outer finished water of the water storage tank is310. Specifically, the water inlet and outlet3400of the joint is disposed on the central tube3300of the joint, and serves as a water inlet and outlet for finished water to flow in and out of channel310of the central tube3300of the joint and the water storage tank. Because the water storage bag may be distorted and deformed in the water-squeezing process, the chamber300may be divided into independent spaces that do not communicate with one another, leading to the possibility that a portion of finished water cannot be squeezed out fully. However, in a case where a central tube3300is disposed, the central tube3300is made of a hard material. Even if deformation occurs in the water storage bag3100, the deformation happens around the central tube3300, which can prevent the chamber300of the water storage bag from being divided into independent spaces that do not communicate with one another. In other words, the central tube3300can prevent distortion of the water storage bag, so as to ensure that all finished water is squeezed out completely from the chamber300of the water storage bag.

FIG. 7is a schematic cross section of a water storage tank in a water-squeezing state. In this state, the joint3200of the water storage bag assembly3000is fixed within the flange4500of the tank by the top cap; the water inlet and outlet3400of the joint contacts the O-ring seal5400; and the top cap chamber500is divided into two chambers that do not communicate with each other, i.e., inner and outer chambers of the joint of the water storage bag respectively; the inner chamber is a finished water100channel and the outer chamber is a squeezed water200channel.

In the state as shown inFIG. 7, the water storage bag3100is completely filled up with finished water. Because the water storage bag3100is designed to have a surface area greater than or equal to the surface area of the inner wall of the water storage chamber400, it can be completely attached to the inner wall of the water storage chamber400, thereby not allowing any squeezed water to remain within the tank; this also makes it possible to allow the space in the tank to be completely used for storing finished water100. Specifically, in the upper chamber430area of the tank, the flow guiding groove4200still keeps an extremely small amount of squeezed water therein;

and these flow guiding grooves4200are connected in communication with the squeezed water channel200of the top cap chamber. When squeezed water200is driven by an external pressure, it enters from the channel520at the top cap of the water storage tank, to the round hole channel420for squeezed water along a channel formed by an outside area of the joint3200of the water storage bag and the inner side area of the top cap; squeezed water200then enters a space between the inner wall of the tank and the water storage bag3100along the flow guiding groove4200and begins to put a pressure on the water storage bag3100under the action of pressure, thereby forcing finished water within the water storage bag to flow out along the central tube3300and the water inlet and outlet3400of the joint. In the case that the pressure of squeezed water is stable, the output of finished water is also maintained at a stable flow.

Because the water storage bag3100is completely come in contact with the inner wall of the tank chamber400, such a long-term contact therebetween may make it difficult for the water storage bag to be separated from the inner wall of the tank, making it difficult for squeezed water to rapidly enter a space between the water storage bag and the inner wall of the tank. This difficulty also prolongs the response time for outputting finished water from the water storage tank; a user would have to wait for a longer time before water flows out of the tank. The design of the flow guiding groove4200in the present invention resolves the above problem by facilitating the flow speed of squeezed water, which then enters the space between the water storage bag and the inner wall of the tank in a fast manner, thereby shortening the response time for outputting finished water from the water storage tank and waiting time for the user.

FIG. 8is a schematic view of a position after a top cap5000of a water storage tank is mounted to the tank. As described above, a threaded connection is used between the top cap and the tank. Because the mounting position of the top cap cannot be controlled accurately in the process of rotationally mounting the top cap to the tank, the ring seal4300may be ineffective and water leakage will happen if the top cap fails to be mounted to the top cap accurately. For the convenience of mounting and positioning of the top cap, in the example shown inFIG. 8, positioning marks5800and4800are disposed on the top cap5000and the tank4000. The mark5800is in a strip form, located on the top cap5000and distributed around the axis of the top cap, and has a certain angle range; and the mark4800is a triangle and located on the tank4000, and points towards the mark5800. In the final stage of mounting the top cap, the top cap will be indicated as being mounted in place as long as the mark4800points towards the strip range of the mark5800. The design of positioning marks5800and4800facilitate an accurate mounting and positioning of the top cap and prevents water leakage resulting from improper mounting.

At the same time, in order to further validate feasibility of the present invention, a water storage tank according to the present invention meeting a certain size requirement was designed. Analysis of structural strength was performed thereon by a finite element simulation software to ensure the feasibility of the example of the water storage tank in engineering and the reliability thereof in the performance of structural strength. The cylindrical chamber of the inner chamber within the water storage tank has a diameter of about 130 mm and has chambers on both ends designed as ellipsoids; and the inner chamber has a total height of about 255 mm and a total volume of about 3 L; and the tank body of the water storage tank has a wall thickness of about 6 mm. In the analysis with the finite element simulation software, a modified polypropylene material is used for the water storage tank. The analysis results show that the water storage tank can withstand a water pressure exceeding 300 psi; and a common municipal water supply has a pressure of 20 to 60 psi, indicating that the strength of the water storage tank according to the present invention can sufficiently meet the application environment of household water purification.

In summary, the design of the water storage tank according to particular embodiments of the present invention improves the utilization rate of finished water storage space of the water storage tank; shortens the response time for outputting finished water from the water storage tank; provides a stable flow of water output. At the same time, the design of the water storage tank of the present invention also addresses the problem that some finished water cannot be completely squeezed out due to distortion of the water storage bag. Moreover, the embodiments employ a design of a cylindrical water storage tank with ellipsoidal or hemispherical ends; the structural strength of the tank is then ensured while the external diameter of the tank is reduced to facilitate the integration design of a water storage tank and a household reverse osmosis water purifier. Also, in the water storage tank according to the embodiments of the present invention, a design of the removable top cap and the ring seal makes replacement of the water storage bag more convenient, which also improves the reliability, the hygiene, and the convenience of the water storage tank.

It can be understood that the above particular embodiments are only exemplary embodiments employed for illustrating the principles of the present invention; the embodiments are not meant to be limiting the present invention. For those of ordinary skill in the art, various variations and modifications may be made without departing from the spirit and essence of the present invention. These variations and modifications shall also be considered as falling within the protection scope of the present invention.