Household water purifier

A household water purifier, comprising a main unit and a filter assembly arranged in the main unit, wherein the filter assembly comprises a composite filter core;

• the composite filter core comprises a filter bottle and a filter element, the filter element is arranged in the filter bottle, and the filter element is of a separated structure, wherein the filter element comprises a polypropylene (PP) melt-blown filter layer, a sintered activated carbon rod and a reverse osmosis membrane, and the PP melt-blown filter layer is sleeved on the sintered activated carbon rod, a first gap formed between the PP melt-blown filter layer and the filter bottle is configured as a water inlet channel, and the sintered activated carbon rod is sleeved on the reverse osmosis membrane, and a second gap formed between the sintered activated carbon rod and the reverse osmosis membrane is configured as a water flow channel;
• the reverse osmosis membrane is hollow and cylindrical, a hollow portion of the reverse osmosis membrane is configured as a purified water channel;
• and
• an expansion unit detachably connected to the main unit, wherein the expansion unit comprises a booster pump for pressurizing a water path,
• wherein when the main unit is not connected to the expansion unit, the household water purifier is operable without being driven by electric power;
• and
• when the main unit is connected to the expansion unit, the expansion unit is arranged between the PP melt-blown filter layer and the sintered activated carbon rod, the booster pump pressurizes the water path to enable the household water purifier to operate by electric power;
• wherein the expansion unit further comprises a low pressure switch and a water inlet solenoid valve;
• the low pressure switch and the water inlet solenoid valve are connected with the booster pump, the low pressure switch is arranged close to the PP melt-blown filter layer;
• the booster pump is arranged close to the sintered activated carbon rod;
• the water inlet solenoid valve is located between the low pressure switch and the booster pump, such that an inlet water flows out of the PP melt-blown filter layer, passes through the low pressure switch and the water inlet solenoid valve, and is pressurized by the booster pump to flow into the sintered activated carbon rod and the reverse osmosis membrane;
• the reverse osmosis membrane is connected with a concentrated water solenoid valve;
• wherein the main unit comprises a reserved connector and a pipe plug, and the pipe plug is detachably connected to the reserved connector;
• the expansion unit comprises a switching plug fitted into the reserved connector;
• when the main unit is connected to the expansion unit, the reserved connector is connected to the switching plug;
• sealing elements are arranged between the reserved connector and the pipe plug as well as between the reserved connector and the switching plug, respectively.