Abstract:
In a hot water distribution system, the water oscillation in hot water supply line maintains hot water line in heated condition by ensuring heat transfer from the water heater to a hot water line executing regenerative heat transfer technique. Fulfillment of longitude water oscillations is ensured by installation of at least two flexible elements such as pressure air accumulators, wherein one is connected to water heater reservoir, and another is connected to hot water line in vicinity to most remote hot water fixture. 
     This can be combined with one of pressure air accumulators initiator of water oscillations that is used for initiation and maintaining of the water oscillation. Heat spreads through the hot water line ensuring hot state of water near all fixtures of the line ensuring instantaneous hot water supply at moment of tap opening.

Description:
The present invention relates to a provisional patent application Ser. No. 60/475,492 filed at the United States patent and trademark office on the 4 th  of Jun. 2003. 

   FIELD OF THE INVENTION 
   The present invention is related to hot water distribution systems. More particularly, the present invention is related to immediate hot water delivery systems. 
   BACKGROUND OF THE INVENTION 
   In many hot water supply systems, such as ones used in homes, the start of hot water consumption mostly includes loss of immense amount of water, inconvenience and even chill during waiting for hot water arrival to the tap. 
   In known immediate hot water delivery system, hot water line from the heater to the tap is kept from chilling by circulation or by reciprocation of hot water between hot and cold water pipes. 
   Closest patent based on circulation principle is aspirator water circulation apparatus disclosed in European Patent Application EP 0 809 079 A1. U.S. Pat. No. 6,026,844 is related to storing hot water in an insulated reservoir and after the stored volume returns to the system, storing is repeated. U.S. Pat. No. 6,227,235 teaches a reciprocate circulation of water between hot and cool lines. Main disadvantages of commercially available circulation and reciprocation instantaneous hot water delivery are high production cost, high electricity consumption, and poor service characteristic. No analogues based on heat transfer along hot water lines have been found. 
   SUMMARY OF THE INVENTION 
   Heat transfer from water heater into hot water line in accordance with regenerative heat transfer technique ensures instantaneous hot water delivery to hot tap even when taps are closed in position. The process is maintained by longitude water oscillations, caused by inserting at least two flexible elements into the hot water system: an air pressure accumulator and a water oscillations initiator. 
   It is an object of the present invention to provide immediate hot water supply device with a longitude heat transfer that ensures at least one of the following: good service, hot water temperature is close to that of heater water, significantly low cost, less power consumption, and easy installation. 
   It is another object of the present invention to provide an immediate hot water supply device that is produced without a motor, in absence of pump and the electrical power is small because it only maintains natural water oscillations in the pipe. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An exemplary embodiment of the invention is described in the following section with respect to the drawings. The same reference numbers are used to designate the same or related features on different drawings. The drawings are generally not drawn to scale. 
       FIG. 1  illustrates an immediate water supply system in accordance with a preferred embodiment of the present invention. 
       FIG. 2  illustrates air pressure accumulator in accordance with a preferred embodiment of the present invention. 
       FIG. 3  illustrates a water oscillations initiator in accordance with a preferred embodiment of the present invention. 
       FIG. 4  illustrates an immediate water supply system in accordance with another preferred embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   The following detailed description is of the best presently contemplated modes of carrying out the present invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles in accordance with the present invention. The scope of the present invention is best defined by the appended claims. 
   Reference is now made to  FIG. 1  illustrating an immediate water supply system in accordance with a preferred embodiment of the present invention. Immediate hot water delivery system  100  comprises water heater  1  that is connected to cold water supply by line  2  and includes oil or gas burner or other built in heating element  3 , which heats water in water heater reservoir  4 . Hot water reservoir  4  is connected to hot water line  5  that delivers hot water to one or several optional hot water taps  6 . Tap  7  is the most remote hot water supply fixture of line  2 . 
   If all taps on line  2  are in closed position, the temperature of water in the line will reach an ambient temperature. Starting the flow of hot water from a tap causes loss of some water before it become suitable for use. Besides water loss, waiting create inconvenience in the customer&#39;s side and sometimes chill of people in bathroom. The use of cold water instead of hot water in kitchen often provokes dermatitis of housewife hands. 
   It is an object of the present invention to ensure immediate water supply to all fixtures. Air pressure accumulator  8  provided in the system and connected to the hot water line  5  in vicinity of most remote tap  7 . Water oscillations initiator  9  consists of air pressure accumulator, combined with water oscillations driver is inserted in water supply system  100  and is fluidically connected to heater reservoir  4 . Water oscillations initiator  9 , together with air pressure accumulator  8  creates longitude oscillation for water between heater reservoir  4  and remote air pressure accumulator  8 . Oscillating system that is organized by elastic supports, air chambers of pressure accumulator  8  and water oscillations initiator  9  together with mass of pipe water used to oscillate water and to fulfill regenerative heat transfer along the hot water line that heats water using heat of water heater. 
   Optionally, cold water supply by line  2  is connected to the bottom of water heater  1 . Optionally, cold water supply by line  2  is equipped with non-return valve (not shown) that prevents hot water from heater  1  to return into the cold water system. Optionally, heater  1  is equipped with a safety pressure release valve preventing system rupture due to overpressure. 
   Optionally, hot water line  5  is connected to the top portion of heater  1 , where the water temperature is higher. 
   Optionally, oscillations initiator  9  is connected to cold water line  2 , close to heater  1 . In this configuration, oscillations initiator  9  is connected between heater  1  and the optional non-return valve. 
   An advantage of the above-described system is that it can easily installed in existing hot water systems converting them to immediate hot water delivery systems. 
   In contrast to water circulation method, no return water pipes need to be installed. Oscillations initiator  9  may easily be installed near the water heater, where electric power supply is readily available. Air pressure accumulator  8  may be installed out of sight under the kitchen sink. 
   If more than one hot water lines  5  are used or if hot water line  5  is branches, it is preferable to install an air pressure accumulator near each of the terminal most remote tap  7 . 
   Alternately, the locations of oscillations initiator  9  and air pressure accumulator  8  may be reversed. 
   Reference is now made to  FIG. 2  illustrating air pressure accumulator in accordance with a preferred embodiment of the present invention. The figure shows details of an exemplary embodiment of air pressure accumulator  8 . Pressure accumulator  8  consists of air chamber that is connected to hot water line  5  by connection pipe  11 . Bottom part of chamber  10  filled by water  12 . Pressed air  13  is filled in the upper portion of the chamber. Optionally, additional tank  14  is connected to chamber  10  by optional connection lines  15 . The water level oscillates between minimal level  16  and maximal level  17 . Optional air tube  18  and optional air valve  19  may be connected to the top part of chamber  10 . Drain valve  20  is optionally placed on lower part of pressure accumulator  8 . 
   Optional oblique tube  21  is equipped by valve  22  that is open if the system is under the working pressure and is closed if pressure is low. The switch of the valve is provided by standard pressure relay. Tube  21  is connected to chamber  10  in vicinity of minimal water level  16 . 
   Optional separation valve  201  on connection pipe  11  may be closed to separate the pressure accumulator  8  from the hot water line  5  for maintenance, as an example. 
   Alternatively, the function of pressure accumulator  8  may be achieved by using a cylinder and piston system where the piston is moved by the water pressure against air pressure on the other side or against a spring. Elastic membrane may replace the piston in this configuration. 
   Reference is now made to  FIG. 3  illustrating a water oscillations initiator in accordance with a preferred embodiment of the present invention. The figure shows details of an exemplary embodiment of water oscillation initiator  9 . 
   Water oscillation initiator  9  comprises hermetic cylinder  23  that is connected to heater  1  by connection pipe  24 , optionally equipped with valve  25 . The bottom part of the cylindrical core  23  is filled by water  26 , while upper part of the cylinder filled by pressed air  27 . Water oscillation initiator  9  includes piston  28  that separates air and water that fill parts of cylinder  23 . Optionally piston  28  is made of light material, thus it remains in this position by its floatage properties. 
   Optionally, radial clearance between piston  28  and the internal walls of cylinder  23  is between 0.2 and 0.3 mm to avoid semidry friction. Alternatively, piston  28  may be substantially the same diameter as the inner diameter of the cylinder and optionally fitted with O-rings or other means for preventing water  26  from entering air  27 . Piston  28  is mechanically connected to magnetic frame  29  of electromechanical pulse driver. 
   Pulse driver comprises magnetic frame  29 , winding  30  and feedback and automation electric circuitry (not shown). At least part of the cylindrical core  31  between the winding  30  and magnetic frame  29  is made of material that facilitates the conduction of magnetic field created by varying electric current in the winding to the magnetic frame, thus affecting force on the piston. Water oscillation initiator  9  optionally includes sockets  32  that provide option to connect with additional oscillation initiator. 
   Optional oblique tube  33  is equipped with valve  34  that is open if the system is under working pressure and is closed if pressure is low. The switch of the valve is provided with standard pressure relay. Optional tube  33  is connected to the cylinder in vicinity of minimal water level in cylinder  23 . 
   Optional air tube  35  and air valve  36  are connected to the top part of cylinder  23 . 
   Optionally, drain valve  37  is placed on drain passage  38  optionally connected to lower part of the oscillation initiator. 
   Valves  201 ,  19 ,  36  and  38  are used for installation and maintenance. 
   Electromechanical pulse driver is built of standard blocks usually used in electronics for the purpose of operating the oscillations initiator. 
   Mechanical pulses of the driver in one or both dead position(s) ensures water pushing, maintaining continuous back-and-forth motion of water inside hot water pipe  5  between heater and air pressure accumulator  9  installed in vicinity of most distant hot tap  7 . 
   Optionally, automation facilities (not shown) ensure synchronizing of mechanical pulses with frequency of natural oscillations of water mass on two elastic supports i.e. air accumulators  8  and oscillation initiator  9 . Water oscillation and heat transfer along the pipe will be maintained with minimum influx of energy. Automation facilities ensure also an initial pulse to start water oscillations. 
   Volume of air in each accumulator varies dependant of pressure in water supply system  100  and may be regulated by additional tanks  14  (shown in  FIG. 2 ). Volume of air may be adjusted according to the length and diameter of hot water pipe  5 . Similarly, the stroke of the piston may be adjusted. 
   Air chambers charging is executed by pouring water in previously empty chambers or cylinders. 
   Water rising from the bottom into empty chamber or cylinder presses air in the chamber and displaces it into the top portion of the chamber or cylinder. 
   The optional use of additional tanks  14  creates facility to correct and correct air volume to produce oscillating system that keeps optimal frequency of natural oscillations and optimal amplitude of oscillations within allowances. This charging method ensures automatic charging after deterioration of water supply. 
   Optionally, if additional air will liberate from water the optional oblique passages  21  or  33 , which are equipped with valves  22  and  34 , respectively that are open if system is under working pressure and are closed if pressure is low will put excessive air into water supply system. The connection point of the optional oblique passages  21  and  33  may be adjusted to the working conditions of the system during installation. 
   Alternatively, the function of oscillation initiator  9  may be achieved by using any type of pump. For example, but not limited to a cylinder and piston system, the piston can move by a motor. Elastic membrane may replace the piston in this configuration. 
   Reference  1  snow made to  FIG. 4  illustrating an immediate hot water supply device in accordance with another preferred embodiment of the present invention. In this embodiment, hot water heater  102  includes hot water reservoir  39  which contains air filled volume  40  at the top. The volume is used as elastic element at the heater side of hot water line  5 . Hot water  41  is supplied by hot water line  2  to hot water tap(s)  6  including most remote fixture of the line  7 . 
   Water oscillation initiator  9  is connected to pipe in vicinity of most remote tap  7 . 
   Hot water oscillating is maintained by elastic air volume of heater tank and water oscillations initiator  9  with its air chamber together with mass of water in the pipe, thus fulfilling regenerative heat transfer along hot water line that heats water using the heat of water heater. 
   If more than one hot water lines  5  are used or if hot water line  5  is branches, it is preferable to install a Water oscillation initiator near each of the terminal most remote tap  7 . 
   Alternately or additionally, an air filled balloon may be inserted into hot water heater  102  inside the hot water reservoir  39 . 
   Optionally, cold water supply by line  2  connected to heater  102  is equipped with non-return valve (not shown), which prevents hot water from heater  1  to return into the cold water system. Optionally heater  101  is equipped with a safety pressure release valve preventing system rupture due to overpressure. 
   Optionally, hot water line  5  is connected to the top of heater  1 , where the water temperature is higher. 
   While the invention has been described with reference to certain exemplary embodiments, various modifications will be readily apparent to and may be readily accomplished by persons skilled in the art without departing from the spirit and scope of the above teachings. 
   It should be understood that features and/or steps described with respect to one embodiment may be used with other embodiments and that not all embodiments of the invention have all of the features and/or steps shown in a particular figure or described with respect to one of the embodiments. Variations of embodiments described will occur to persons of the art. 
   It is noted that some of the above described embodiments may describe the best mode contemplated by the inventors and therefore include structure, acts or details of structures and acts that may not be essential to the invention and which are described as examples. Structure and acts described herein are replaceable by equivalents which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the invention is limited only by the elements and limitations as used in the claims. The terms “comprise”, “include” and their conjugates as used herein mean “include but are not necessarily limited to”.