Abstract:
A reverse osmosis (RO) water filtration device includes a body, a RO cartridge, a first cartridge, a second cartridge and a storage tank all mounted inside the body. Water to be filtered sequentially goes through a water inlet of the RO water filtration device, the first cartridge, the RO cartridge, the storage tank, the second cartridge, and a faucet to get the water filtered. The storage tank provides additional water supply when the pressure between the faucet and RO cartridge is below the water pressure inside the storage tank to increase water volume upon opening a faucet.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a reverse osmosis (RO) water filtration device and, more particularly, to an RO water filtration device with water storage function. 
         [0003]    2. Description of the Related Art 
         [0004]    Conventional reverse osmosis (RO) water filtration devices with small capacity of treated water under 300 G in the current market need to be equipped with an extra storage tank to meet the demand of flow rate when the faucet is opened. Also because the RO water filtration devices are usually mounted inside kitchen cabinets, the additional storage tank is space-taking and inconvenient to use and the water in the storage tank is easily contaminated by bacteria. 
       SUMMARY OF THE INVENTION 
       [0005]    An objective of the present invention is to provide a RO water filtration device and a method for operating the RO water filtration device. 
         [0006]    To achieve the foregoing objective, the RO water filtration device includes a body, a first cartridge, an RO cartridge, a storage tank and a second cartridge. 
         [0007]    The body has a water inlet, a filtered water outlet and a waste water outlet formed in a periphery of the body. The filtered water outlet is connected with and communicates with a faucet. 
         [0008]    The first cartridge is mounted inside the body and is connected with and communicates with the water inlet through a channel formed inside the body. 
         [0009]    The RO cartridge is mounted inside the body and has an inlet, an outlet and an RO waste water outlet. 
         [0010]    The inlet is connected with and communicates with the first cartridge through a channel formed inside the body. A pump is mounted to the channel between the RO cartridge and the first cartridge. 
         [0011]    The RO waste water outlet is connected and communicates with the waste water outlet through a channel formed inside the body. 
         [0012]    The storage tank is mounted inside the body, is connected with and communicates with the outlet of the RO cartridge through a channel formed inside the body, and has a liner mounted on an inner wall of the storage tank. The liner is made of a resilient material. 
         [0013]    The second cartridge is mounted inside the body, and is connected with and communicates with the filtered water outlet and the storage tank respectively through two channels formed inside the body. A high-pressure switch is mounted to the channel between the second cartridge and the storage tank to control operation of the pump. 
         [0014]    When the faucet is closed, the pump is operated to fill the storage tank with filtered water until a water pressure of filtered water inside the storage tank sensed by the high-pressure switch reaches a water pressure threshold, and when the faucet is open and a water pressure between the storage tank and the second cartridge sensed by the high-pressure switch drops below the water pressure threshold, the filtered water inside the storage tank pushed out by the liner of the storage tank and filtered water outputted from the RO cartridge flows to the faucet. 
         [0015]    To achieve the foregoing objective, the method for operating an RO water filtration device includes steps of:
       closing the faucet;   operating the pump at an output water pressure;   stopping the pump from operating when a water pressure between the RO cartridge and the faucet reaches a water pressure threshold, wherein the water pressure threshold is lower than the output water pressure, and the storage tank is filled with filtered water at the water pressure threshold and the liner of the storage tank is squeezed by the filtered water inside the storage tank;   opening the faucet for a water pressure between the RO cartridge and the faucet to drop; and   starting the pump when the water pressure between the RO cartridge and the faucet is below the water pressure threshold, wherein the filtered water in the storage tank pushed out of the storage tank by the liner and the filtered water outputted from the RO cartridge flow to the faucet.       
 
         [0021]    When compared to conventional techniques, the present invention has the following advantages that because the storage tank and all the cartridges are all mounted inside the body, the issues arising from insufficient space and aesthetic concern can be tackled, production cost can be reduced, and bacteria contamination in the storage tank can be resolved. 
         [0022]    Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a functional block diagram of an RO water filtration device with water storage function in accordance with the present invention; 
           [0024]      FIG. 2  is a schematic top view of the RO water filtration device in  FIG. 1 ; and 
           [0025]      FIG. 3  is a cross-sectional view of a storage tank of the RO water filtration device in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    With reference to  FIGS. 1 and 2 , an RO water filtration device in accordance with the present invention includes a body  100 , a RO filter cartridge  140 , a first cartridge  150 , a second cartridge  160  and a storage tank  170 . 
         [0027]    The body  100  has a water inlet  110 , a filtered water outlet  120  and a waste water outlet  130 . The water inlet  110  and the waste water outlet  130  are mounted in a first lateral portion of the RO water filtration device  100 , and the filtered water outlet  120  is mounted in a second lateral portion opposite to the first lateral portion. 
         [0028]    The first cartridge  150  is mounted inside the body  100  and has a first inlet  151  and a first outlet  152 . The first inlet  151  communicates with the water inlet  110  through a first channel  210  formed inside the body  100  and connected between and communicating with the first inlet  151  and the water inlet. A low-pressure switch  380  is mounted to the first channel  210 . The first outlet  152  communicates with the RO cartridge  140  through a second channel  220  formed inside the body  100  and connected between and communicating with the first cartridge  150  and the RO cartridge  140 . A solenoid valve  320 , a water TDS (total dissolved solids) transducer  330  and a pump  340  are mounted to the second channel  210 , and the pump  340  is electrical connected with the low-pressure switch  380 . The solenoid valve  320  is to control water flows direction and flow speed. The water TDS transducer  330  is to detect any minerals, salts, metals, cations or anions dissolved in water. 
         [0029]    The low-pressure switch  380  has a controller  381 , and the low-pressure switch  380  detects a water pressure into the first channel  210 . When the water pressure is low or no pressure at all, the controller  381  sends a signal to the pump  340  to stop the pump  340  from working. 
         [0030]    The RO cartridge  140  is mounted inside the body  100  and has an inlet  141 , an outlet  142  and a RO waste water outlet  143 . The inlet  141  communicates with the first cartridge  150  through the second channel  220 . The outlet  142  communicates with the storage tank  170  through a third channel  230 . A check valve  310  is mounted into the outlet  142 . The RO waste water outlet  143  communicates with the waste water outlet  130  through a fifth channel  250  formed inside the body  100  and connected between and communicating with the RO waste water outlet  143  and the waste water outlet  130 , and water containing impurities flows out of the waste water outlet  130  through the RO waste water outlet  143  and the fifth channel  250  sequentially. 
         [0031]    The storage tank  170  is mounted inside the body  100  and has a storage tank inlet  172  and a storage tank outlet  173 . The storage tank inlet  172  communicates with the RO cartridge  140  through a third channel  230  formed in the body  100  and connected between the storage tank  170  and the RO cartridge  140 . The storage tank outlet  173  is connected with and communicates with a fourth channel  240  formed in the body  100  and connected between the storage tank  170  and a second cartridge  160 . With reference to  FIG. 3 , a liner  171  is mounted on an inner wall of the storage tank  170  and is made of a resilient material. 
         [0032]    The second cartridge  160  is mounted inside the body  100  and has a second inlet  161  and a second outlet  162 . The second inlet  161  is connected with and communicates with the fourth channel  240 . The second outlet  162  is connected with and communicates with the filtered water outlet  120  through the fourth channel  240 . 
         [0033]    A flowmeter  370 , a high-pressure switch  350 , and a filtered water TDS transducer  360  are mounted to the fourth channel  240 . The filtered water TDS transducer  360  is to detect any minerals, salts, metals, cations or anions dissolved in water. A controller  351  is mounted into the high-pressure switch  350 , and the high-pressure switch  350  is electrical connected with the pump  340 . The high-pressure switch  350  senses the water pressure in the storage tank  170  and is switched to be open or closed by the water pressure in the storage tank  170 , and respectively sends a start signal and a stop signal to the controller  351  when the water pressure in the storage tank  170  is below 40 psi and when the water pressure in the storage tank  170  reaches 40 psi. 
         [0034]    The filtered water outlet  120  communicates with the second outlet  162  of the second cartridge  160  through a sixth channel  260  formed inside the body  100  and connected between and communicating with the filtered water outlet  120  and the second outlet  160 , and is connected with and communicates with a faucet  400 . 
         [0035]    Operation of the RO water filtration device  100  is described as follows. Water to be filtered enters the water inlet  110  of the RO water filtration device  100 , and flows in the first cartridge  150  through the first channel  210 . Water filtered by the first cartridge  150  flows out of the first cartridge  150  through the first outlet  152 , then flows through the second channel  220 , the solenoid valve  320 , the TDS transducer  330  and the pump  340 . After the pressure of water in the pump  340  is boosted to be stable, water in the pump  340  flows out and then enters the RO filter cartridge  140  through the inlet  141  of the RO filter cartridge  140 . Impurities in water pass through the osmosis membrane and are removed and filtered water flows out of the outlet  142 . Meanwhile, water containing impurities flows to the waste water outlet  130  of the RO water filtration device  100  through the RO waste water outlet  143  and the fifth channel  250 . Filtered water flow from the outlet  142  flows through the third channel  230  and then enters the storage tank  170  through the storage tank inlet  172 . A portion of filtered water is stored in the storage tank  170 , the remaining portion of filtered water flows out of the storage tank  170  through the storage tank outlet  173 , and then enters the second cartridge  160  through the fourth channel  240 . Filtered water enters the second cartridge  160  through the second inlet  161  and reacts with the second cartridge  160 , and water flowing out of the second outlet  162  further flows to the faucet  400 . 
         [0036]    In normal use, water pressure between the pump  340  and the RO cartridge  140  is 70 psi. After the faucet  400  is closed, water is detained inside the RO water filtration device  100 , and the pump  340  is started operating to pump out the water in the pump  340 . Filtered water flowing out of the RO cartridge  140  flows in the storage tank  170  to fill the storage tank  170  and squeeze the liner  171 . After the storage tank  170  is fully filled, the water pressure acted on the liner  171  of the storage tank  170  is 40 psi and filtered water further enters the fourth channel  240 . When the water pressure of the fourth channel  240  detected by the high-pressure switch  350  reaches 40 psi, the controller  351  receives the stop signal from the high-pressure switch  350  and sends a signal to the pump  340  to stop the pump  340  from working. 
         [0037]    When the faucet  400  is opened, filtered water flows out of the faucet  400 , water pressure between the RO cartridge  140  and the faucet  400  drops. Once the water pressure of the fourth channel  240  sensed by the high-pressure switch  350  drops below 40 psi, the controller  351  sends another signal to the pump  340  for the pump  340  to start working. Further, as the pressure acted on the liner  171  of the storage tank  170  is 40 psi, which is higher than the pressure in the fourth channel  240 , the liner  171  releases its elastic force to push the filtered water out of the storage tank  170 . Both filtered water from the storage tank  170  and filtered water outputted from the outlet  142  flows to the faucet  400  to increase water flow out of the faucet  400 . 
         [0038]    As the storage tank  170  and all the cartridges  140 ,  150 ,  160  are all mounted inside the body  100 , the issues arising from insufficient space and aesthetic concern can be tackled, production cost can be reduced, and bacteria contamination in the storage tank can be resolved. 
         [0039]    Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.