1. Field of the Invention
The present invention relates to water heating technology and more particularly, to a water inlet/outlet reversible water heater for use in an aquarium, which enables water to flow through the tube body of the heating tube thereof and to be heated by a heating element around the tube body subject to the control of a circuit control device outside a casing that holds the heating tube therein, preventing the circuitry from thermal damage.
2. Description of the Related Art
A water heater for use in an aquarium or like apparatus generally comprises a heating tube having a heating wire mounted in an inside wall of a tube body thereof. When the heating wire is electrically conducted, a heat energy is released from the heating wire and transferred through the peripheral wall of the tube body to heat the surrounding fluid (such as water), raising the temperature of the fluid (water) in the aquarium or like apparatus.
In application, the water heater 10 is dipped in the fluid (for example, water) 15 to be heated. During operation, the heat energy released by the heating wires 11 is transferred through air in gaps 13 in the glass tube 12 and the tube wall 14 of the glass tube 12 to heat the fluid (water) 15. Conventional water heaters for aquarium commonly adopt this heating method of heating water outside the heating tube.
However, this prior art design of water heater 10 is still not satisfactory in function. Because the air exists in the gaps 13 in the glass tube 12 is a poor conductor of heat that significantly impede transfer of heat, the heat energy released by the heating wires 11 cannot be immediately and efficiently through the tube wall 14 of the glass tube 12 of high temperature resistant insulation material to heat the fluid (water) 15. Therefore, the overall heating efficiency of this prior art design of water heat is low. Further, the design of water heater is not environmentally friendly and it consumes a large amount of energy during operation. Further, during operation, the internal temperature of the water heater 10 will become high, and the related internal control circuit can be easily thermally damaged, shortening the lifespan of the water heater.
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a water inlet/outlet reversible water heater, which enables water to be guided through a heating tube and directly heated by the heating tube, improving the heating efficiency of the heater. It is another object of the present invention to provide a water inlet/outlet reversible water heater, which has the operation of the heating tube be controlled by an external circuit control device, preventing the circuitry from thermal damage.
To achieve these and other objects of the present invention, a water inlet/outlet reversible water heater comprises a heating tube and a casing. The heating tube comprises a tube body made from a high temperature resistant insulation material and defining therein an axial center hole, and a heating element surrounding the outer perimeter of the tube body. The casing holds the heating tube therein having a water hole located in each of two opposite ends thereof in communication with the axial center hole of the tube body for the passing of the water to be heated. When water is guided through the water holes of the casing and the axial center hole of the tube body, it is heated efficiently and economically by the heat energy that is released by the heating element and transferred through the peripheral wall of the tube body. Further, because the related control circuit is disposed outside the heating tube, the related control circuit will not be damaged easily, and thus, the lifespan of the water inlet/outlet reversible water heater can be significantly prolonged.
Preferably, the casing comprises an axial center hole extended through two opposing ends thereof, and two end caps respectively capped on the two opposite ends thereof. Each end cap defines therein one water hole in communication with the axial center hole of the tube body of the heating tube. The tube body of the heating tube comprises two positioning portions respectively extended from two opposite ends thereof and positioned in the axial center hole of the casing, and a plurality of gasket rings respectively mounted around the positioning portions and abutted against an inside wall of the casing to seal the gap between the casing and the tube body of the heating tube.
Preferably, the water inlet/outlet reversible water heater further comprises a circuit control device fastened to an outside wall of the casing outside the heating tube, and adapted for controlling the operation of the heating element of the heating tube.
Preferably, the circuit control device comprises a power cable located at one end thereof for connection to an external power source, a circuit board mounted on the inside, opposing water-sealing bottom cover and top cover respectively covered on opposing top and bottom sides thereof in a watertight manner, and a plurality of plug holes for the mounting of the casing. Further, the casing comprises a plurality of plug rods extended from the periphery thereof and respectively plugged into the plug holes of the control circuit device, and a plurality of gasket rings mounted in between the plug rods and the plug holes.
In another embodiment of the present invention, the water inlet/outlet reversible water heater comprises a heating tube, a casing, and a circuit control device. The heating tube comprises a tube body made from a high temperature resistant insulation material and defining therein an axial center hole, and a heating element surrounding the outer perimeter of the tube body. The casing holds the heating tube therein, having a water hole located in each of two opposite ends thereof in communication with the axial center hole of the tube body for the passing of the water to be heated. The circuit control device fastened to an outside wall of the casing outside the heating tube, and adapted for controlling the operation of the heating element of the heating tube.
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In operation, water 15 is guided through the water holes 28 of the end caps 29 and the axial center hole 21 of the tube body 20, and heated efficiently and economically by the heat energy that is released by the heating element (heating wire or heating film) 23 and transferred through the peripheral wall of the tube body 20. Further, because the related control circuit is disposed outside the heating tube 25, the related control circuit will not be damaged easily, and thus, the lifespan of the water inlet/outlet reversible water heater can be significantly prolonged.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.