Vacuum insulated storage-type electric water heater having an external bubble pump heating unit

Claim 2

A hot water boiling apparatus comprising: a hot water storage tank including an inner tank adapted to store water therein and having a top wall, and an outer tank enclosing the inner tank, and a vacuum heat insulation space defined between the inner and outer tanks and substantially completely surrounding the inner tank; a hot water supply pipe for guiding the water from an upper portion of the inner tank to the outside of the hot water tank, said supply pipe having an end portion connected to the top wall of the inner tank and passing through the vacuum insulation space and the outer tank air-tightly, said supply pipe having an insulation portion located in the vacuum insulation space and extending substantially horizontally through the vacuum space to the outer tank; water supply means for supplying a lower portion of the inner tank with water; and flow-type water heating means arranged external of the water storage tank in flow communication with the water storage tank, for drawing the stored water from the lower portion of the inner tank and, after heating the water, returning the heated water into the upper portion of the inner tank, said heating means including a connecting pipe which introduces the heated water into the inner tank and has an end portion connected to the top wall of the inner tank and passing through the insulation space and the outer tank air-tightly, said connecting pipe having an insulation portion located in the vacuum insulation space and extending substantially horizontally through the vacuum space to the outer tank.

Claim 3

An apparatus according to claim 1, wherein said outer tank includes an top wall facing the top wall of the inner tank and a side wall substantially extending vertically, and said insulation portions of the connecting pipe and hot water supply pipe passing through the side wall of the outer tank.

Claim 4

An apparatus according to claim 1, wherein said connecting pipe has a second end portion connected to the lower portion of the inner tank and passing through the insulation space and the outer tank air-tightly, and said heating means includes bubble pump means which comprises a boiling chamber defined in the connecting pipe, a heater for heating water in the boiling chamber and generating steam bubbles in the water, and guide means associated with said boiling chamber for feeding the water, introduced through the second end portion of the connecting pipe, into the boiling chamber and condensing the steam bubbles by the water fed through the guide means.

Claim 5

A hot water boiling apparatus comprising: a hot water storage tank including an inner tank adapted to store water therein, and an outer tank enclosing the inner tank, and a vacuum heat insulation space defined between the inner and outer tanks and surrounding the inner tank; a hot water supply pipe for guiding the water from an upper portion of the inner tank to the outside of the hot water tank; water supply means for supplying a lower portion of the inner tank with water; and bubble pump means arranged external of said hot water storage tank, for feeding hot water into the upper portion of the inner tank after drawing the water from the lower portion of the inner tank and heating the drawn water, said pump means including a body having a boiling chamber, heating means for heating water in the boiling chamber and generating steam bubbles in the water, a first connecting pipe for guiding the water from the lower portion of the inner tank to the pump means body, a guide pipe in said body for feeding the water, guided through the first connecting pipe, into the boiling chamber and condensing the steam bubbles by the water fed through the guide pipe, a second connecting pipe for guiding the water heated in the boiling chamber into the upper portion of the inner tank, and first and second regulating means arranged in the first and second connecting pipes, for allowing the water to flow only from the lower portion of the inner tank toward the upper portion of the inner tank, said guide pipe being so arranged with respect to said pump means body that heat is exchanged between the water in the boiling chamber and the water flowing through the guide pipe.

Claim 6

A hot water boiling apparatus comprising: a hot water storage tank including an inner tank adapted to store water therein, and an outer tank enclosing the inner tank, and a vacuum heat insulation space defined between the inner and outer tanks and surrounding the inner tank; a hot water supply pipe for guiding the water from an upper portion of the inner tank to the outside of the hot water tank; water supply means for supplying a lower portion of the inner tank with water; and bubble pump means arranged external of said hot water storage tank, for feeding hot water into the upper portion of the inner tank after drawing the water from the lower portion of the inner tank and heating the drawn water, said pump means including a body having a boiling chamber, heating means for heating water in the boiling chamber and generating steam bubbles in the water, a first connecting pipe for guiding the water from the lower portion of the inner tank to the pump means body, a guide pipe in said body for feeding the water, guided through the first connecting pipe, into the boiling chamber and condensing the steam bubbles by the water fed through the guide pipe, a second connecting pipe for guiding the water heated in the boiling chamber into the upper portion of the inner tank, and first and second regulating means arranged in the first and second connecting pipes, for allowing the water to flow only from the lower portion of the inner tank toward the upper portion of the inner tank, said guide pipe being so arranged with respect to said pump means body that heat is exchanged between the water in the boiling chamber and the water flowing through the guide pipe.

Claim 7

An apparatus according to claim 4, wherein said water supply means includes a water supply pipe with one end communicating with the lower portion of the inner tank, one of an end of the first connecting pipe and said one end of the water supply pipe air-tightly passing through the vacuum insulation space and the outer tank and being liquid-tightly connected to the lower portion of the inner tank, the other running within said one of the two pipes and communicating with the lower portion of the inner tank; said hot water supply pipe communicating at one end with the upper portion of the inner tank, one of an end of the second connecting pipe and said one end of the hot water supply pipe air-tightly passing through the outer tank and being liquid-tightly connected to the upper portion of the inner tank, the other running within said one of latter two pipes and communicating with the upper portion of the inner tank.

Claim 8

An apparatus according to claim 4, wherein said heating means comprising an electric heater and includes a sensor for detecting the temperature of water in the inner tank and a power supply system for controlling power supply to the electric heater in response to a detection signal from the sensor.

Claim 9

An apparatus according to claim 6, wherein said sensor is electrical, is provided in the lower portion in the inner tank and is electrically connected to said power supply system through a lead wire extending through the second connecting pipe to the outside of the hot water storage tank.