Patent Publication Number: US-6909842-B2

Title: Instantaneous compact fluid heater

Description:
FIELD OF THE INVENTION 
   The present invention relates to a fluid heater. More specifically, the present invention is concerned with an instantaneous compact water heater for selectively heating water. 
   BACKGROUND OF THE INVENTION 
   Conventional fluid and water heaters include a tank or reservoir containing a predetermined amount of water into which a heating element is positioned. The water inside the tank is maintained at a predetermined temperature so that it is easily available upon demand. A drawback with the conventional water heater is that there is a loss of valuable energy by heat convection out of the tank or reservoir. 
   Accordingly, various structures have been proposed to minimize such heat loss. 
   U.S. Pat. No. 3,952,182 issued to Flanders on Apr. 20, 1976 teaches a miniature instantaneous electric fluid heater adaptable to be mounted immediately in advance of a hot water faucet. The heater includes a fluid-holding heating vessel having at least one heating element to heat the fluid and having an inlet assembly at its bottom end and an outlet assembly at its top end. 
   U.S. Pat. No. 4,459,465 issued to Knight on Jul. 10, 1984 teaches an instantaneous fluid heater having a fluid inlet, a plurality of heating chambers having heating elements and a fluid outlet. The heating chambers are interconnected by means of laterally extending passageways. 
   U.S. Pat. No. 4,900,896 issued to Maus on Feb. 13, 1990 teaches a continues flow heater having a sealed chamber containing an electrical heating element and a diaphragm having an orifice through which water must flow upon demand. The centre of the diaphragm translates axially in response to the water flow and moves an internal magnet, which influences an external magnet to throw a flow switch. 
   U.S. Pat. No. 5,438,642 issued to Posen on Aug. 1, 1995 teaches an instantaneous water heater having an inlet cylinder for receiving water from a supply and an outlet cylinder to discharge heated water. A plurality of heat exchange chambers is formed between the inlet and outlet cylinders. The chambers are positioned in a row and to allow for water to flow in a serpentine manner therethrough. The chambers include heaters controlled by triacs. The inlet cylinder includes a magnet that rises in response to water to close a reed switch in order to turn the power on. 
   A drawback with the prior art is inefficiency, high cost and complicated design. 
   There thus remains a need for an improved water heater. 
   OBJECTS OF THE INVENTION 
   An object of the present invention is therefore to provide an improved water heater. 
   SUMMARY OF THE INVENTION 
   More specifically, in accordance with the present invention, there is provided a fluid heater comprising: 
   a reservoir for containing fluid and including heating elements positioned therein; 
   an inlet-conduit assembly mounted to the reservoir having an inlet-aperture at one end and being in communication with the reservoir at an opposite end; 
   an outlet conduit mounted to the reservoir and being in communication with the reservoir at one end and having an outlet-aperture at an opposite end; 
   a fluid-flow detector assembly mounted to one of the inlet-conduit assembly and outlet conduit; 
   a heating element modulator mounted to the inlet-conduit assembly, the heating element modulator being connected to the heating elements; 
   a thermal sensor mounted to at least one of the inlet-conduit assembly, reservoir and outlet conduit; 
   a controller connected to the heating element modulator, to the fluid-flow detector assembly and to the thermal sensor; 
   whereby, fluid enters the inlet-conduit assembly through its inlet-aperture causing the fluid-flow detector assembly to instruct the controller to activate the heating elements via the heating element modulator; the fluid then flows into the reservoir to be heated by the heating elements and out of the reservoir into the outlet conduit towards the outlet-aperture. 
   In accordance with another aspect of the invention there is provided a body for a fluid-heater, the body comprising: 
   a reservoir defining a cavity for receiving fluid and heating elements therein and including an open end;
         a inlet-conduit assembly mounted to the reservoir and having an inlet aperture at one end and being in fluid communication with the reservoir cavity at another end, the inlet-conduit assembly being configured to receive a heating element modulator; and       

   an outlet conduit mounted to the reservoir and having one end in fluid communication with the reservoir and an outlet aperture at an opposite end; 
   wherein at least one of the inlet-conduit assembly and outlet conduit is configured to receive a fluid-flow detector assembly and at least one of the inlet-conduit assembly, reservoir and outlet conduit is configured to be connected to a thermal sensor. 
   An advantage of the present invention is that the water heater is compact and takes up less space as compared to, prior water heaters. 
   Another advantage of the present invention is that the water heater may selectively heat water upon demand. 
   A further advantage of the present invention is that it minimizes loss of energy out of the reservoir. 
   A further advantage of the present invention is that the water heater while meeting conventional norms is of simple construction, relatively easy to use and economical. 
   Other objects, advantages and features of the present invention will become more apparent upon reading of the following non restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the appended drawings like reference numerals denote like elements throughout and in which: 
       FIG. 1  is an elevational broken front view of the fluid heater in accordance with an embodiment of the present invention; 
       FIG. 2  is an elevational side view of the fluid heater of  FIG. 1 ; 
       FIG. 3  is a top plan view of the fluid heater of  FIG. 1 , shown without a cover and heating elements; 
       FIG. 4  is a sectional view of  FIG. 2  taken along line  4 — 4 ; 
       FIG. 5  is a sectional view of  FIG. 4  taken along line  5 — 5 ; 
       FIG. 6  is a top plan view of the fluid of  FIG. 1 ; 
       FIG. 7  is a partial perspective view of the fluid heater of  FIG. 1 , shown without a cover and heating elements; and 
       FIG. 8  is a schematic drawing showing the controller being mounted to various components of the present invention. 
   

   DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 
   With reference to  FIGS. 1  to  8  an embodiment of the present invention will be herein described. 
   Referring to  FIGS. 1 and 2  there is shown a fluid heater  10  including a fluid-containing reservoir  12 , an inlet-conduit assembly  13  and an outlet conduit  18 . In this embodiment, the inlet-conduit assembly  13  includes an inlet conduit  14  and an auxiliary conduit  16  (FIG.  2 ). Together, the foregoing components form a body  11  (see  FIG. 7 ) for a fluid heater  10 . 
   It should be noted that the term “reservoir” could be construed herein to mean a tank, a water guard or any like water containing body as is known in the art. 
   In most cases, the fluid to be heated by the present fluid heater  10  is water, nevertheless the invention is not limited to the heating of water but may be used to heat other fluids as can be contemplated by the skilled artisan. Therefore, for the purpose of the present disclosure the terms “water” and “fluid” are interchangeable. 
   The reservoir  12  is an elongated cylindrical tank defining a single elongated cavity or chamber  19  (see  FIGS. 3 ,  4  and  7 ) configured to contain water to be heated as will be explained below. Reservoir  12  has an open top end  20  (see  FIGS. 3 and 7 ) and an opposite threaded bottom end  22  defining a drainage aperture  24  which is kept closed during use by a complementary threaded cap  26 . 
     FIG. 1  shows heating elements  28 ,  30  and  32  positioned within the reservoir  12 . The heating elements  28 ,  30  and  32  are secured to a cover  34  (see FIG.  6 ), which is mounted to the reservoir  12  as will be explained below. Each heating element  28 ,  30 ,  32  has a compact configuration in order to minimize the space it occupies inside the reservoir while meeting the standards and norms of common practice. In this particular example, the heating elements  28 ,  30  and  32  are in colloidal, sheathed type and travel in an ‘S’. Each heating element  28 ,  30  and  32  extends beyond cover  34  and terminates with a respective rod  36  beyond each of its two sheathed ends  35  (also see FIG.  6 ). Each rod  36  is soldered by a tab  38  (also see FIG.  6 ). 
   With reference to  FIGS. 1 and 8 , the heating elements  28 ,  30  and  32  are electrically connected to a controller  40  via a heating element modulator, as will be explained herein. 
   The inlet conduit  14  is a longitudinal member such as a pipe defining a channel  41  and positioned along the length of the reservoir  12 . The inlet conduit  14  has a threaded bottom end  42  defining an inlet-aperture  44  and an exit aperture  46  at its top end  43  (see FIGS.  3  and  7 ). 
   As shown in  FIG. 1 , a fluid-flow detector assembly  47  is positioned in the inlet conduit  14  and mounted to the controller  40  (also see FIG.  8 ). 
   The fluid-flow assembly  47  includes a flow-detector  48  in the form of a floatable shuttle or flow switch placed within the inlet conduit  14 . Shuttle  48  includes a magnet  50 . 
   The fluid-flow assembly  47  also includes a sensor  0 . 52  mounted to the inlet conduit  14  at a predetermined position near the exit-aperture  46 . Sensor  52  is configured to be signalled by the flow detector  48  as will be explained below. The sensor  52  is in the form of magnetic contact switch or reed switch. Sensor  52  is mounted to the controller  40  so as to transmit data thereto. 
   As can be seen from  FIG. 2 , the auxiliary conduit  16  is a longitudinal member such as a pipe defining a channel  53  and positioned along the length of the reservoir  12  opposite the inlet conduit  14 . As shown in  FIGS. 3 and 7 , the auxiliary conduit  16  has an aperture  54  at its top end  55  which is communication with the inlet conduit exit-aperture  46  via a channel  56  formed therebetween which provides for channel  41  to be contiguous with channel  53 . With reference to  FIGS. 2 ,  4  and  5 , the auxiliary conduit  16  has a bottom portion  58  in communication with the reservoir  12  via a reservoir entry-aperture  60  which provides for channel  53  to be contiguous with cavity  19 . 
   Water to be heated may thus flow from the inlet  44 , through conduits  14  and  16  to reach the reservoir cavity  19 . 
   With reference to  FIGS. 1 and 2 , the auxiliary conduit  16  is connected to a heating element modulator  62  in such as way as to expose the heating element modulator to cold water as will be explained when the invention is described in operation. 
   With reference to  FIG. 8 , the heating element modulator  62  is connected to the controller  40 . 
   The heating element modulator  62  is in the form of triacs  64 ,  66  and  68 . Each triac  64 ,  66  and  68  is mounted to the auxiliary conduit  16  in a respective triac-aperture  70  allowing each triac  64 ,  66  and  68  to communicate with the auxiliary channel  53 . 
   Each triac  64 ,  66  and  68  is connected to a respective heating element  28 ,  30  and  32  for modulation thereof. For example, triac  64  is electrically connected to heating element  28 , triac  66  is electrically connected to heating element  30  and triac  68  is electrically connected to heating element  32 . The triacs  64 ,  66  and  68  control the electrical current that is supplied to the heating elements  28 ,  30  and  32  as commanded by the controller  40  and as will be discussed herein. 
   The outlet conduit  18  is a longitudinal pipe member defining a channel  69  and positioned along the length of the reservoir  12  on a side thereof that is opposite both the inlet and auxiliary conduits  14  and  16  respectively. The outlet conduit  18  has a top end aperture  72  that is in communication with the reservoir top open end  20  via a channel such as duct  74  (see  FIGS. 3 and 7 ) formed therebetween which provides from cavity  19  to be contiguous with channel  69 . As shown in  FIGS. 1 and 2 , the outlet conduit  18  has a threaded bottom end  76  defining an outlet-aperture  78 . 
   With reference to  FIGS. 1 and 8  the outlet conduit includes a thermal sensor such as a temperature probe  80  which is also connected to controller  40 . As shown in  FIG. 1 , the thermal sensor  80  is mounted in channel  69  near aperture  72 . The thermal sensor  80  is configured to detect the temperature of water flowing through the outlet conduit  18  and to transmit this data to the controller  40 . 
   A thermostat  82  in the form of a disk type thermostat is mounted to the fluid heater  10 . The thermostat  82  is manually operated and configured to disengage electrical supply to the heater elements  28 ,  30  and  32  as will be discussed hereinbelow. 
   As shown, the thermostat  82  may be mounted to the cover  34  or the reservoir  12 . In the latter case, the reservoir  12  includes a thermostat-aperture (not shown) for receiving thermostat  82 . 
   With reference to  FIGS. 3 and 7  the reservoir  12 , inlet, auxiliary and outlet conduits  14 ,  16  and  18  respectively are joined together at their top ends by a common plate  84 . 
   As shown in  FIG. 6 , the cover  34  has a configuration that is complementary to plate  84  and is mountable thereto by way of fasteners (not shown) mountable in cover screw holes  86  which correspond to plate screw holes  88 . In this way cover  34  covers the reservoir open end  20 , the inlet conduit exit-aperture  46 , the auxiliary conduit aperture  54 , the channel  56 , the outlet conduit top end aperture  72  and the duct  74 . 
   The fluid heater  10  is mounted in an enclosure  90  in the form of a box having a removable front cover or door  92  to allow easy access thereto and a back panel  94 . Enclosure  90  also includes apertures at its bottom end which respectively provide for the inlet conduit end  42  and the outlet conduit end  76  to extend beyond the enclosure bottom end  96 . The enclosure  90  is mountable to a wall surface (not shown) via screw holes  98  in back panel  94 . 
   Keeping the above description in mind, the invention will now be described in operation. 
   The fluid heater  10  is mounted to a wall surface (not shown) within the enclosure  90 . The controller  40  is connected to a power supply (not shown) supplying power to the fluid heater  10  as is known in the art. 
   A cold water supply pipe (not shown) is screwed onto the threaded end  44  of the inlet conduit  14  and a hot water outlet pipe (not shown) is screwed onto the threaded end  76  of the outlet conduit  18 . 
   Cold water (not shown) from the supply pipe enters the inlet conduit  14  through the inlet-aperture  44 . The water upwardly flows inside channel  41  of the inlet conduit  14  causing the floatable shuttle  48  to rise therewith. The shuttle  48  reaches the position of the magnetic contact switch  52  and closes it. Hence, when the shuttle magnet  50  and the switch  52  are in magnetic contact, the controller  40  is notified by switch  52  and activates the heating elements  28 ,  30  and  32  as well as the triacs  64 ,  66  and  68 . 
   The water flows out of the inlet conduit through its exit-aperture  46  and is directed towards the auxiliary conduit  16  via channel  56 . The water enters the auxiliary conduit  16  through its top end aperture  54 . As shown, apertures  46  and  54  are adjacent and communicate via the short channel  56 , this provides for there being no dead ends during water flow hence, permitting fluid flow without trapping air. 
   This cold water downwardly flows in the auxiliary conduit channel  53  to directly communicate with the activated triacs  64 ,  66  and  68 , which are cooled down thereby. 
   When the triacs  64 ,  66  and  68  are activated they will tend to over heat; the configuration of the auxiliary conduit is advantageous since it counteracts this overheating factor by allowing cold water to cool the triacs  64 ,  66  and  68  down. 
   The water then enters the reservoir  12  through aperture  60  (see  FIGS. 2 ,  4  and  5 ) and upwardly fills the fluid containing chamber or reservoir  12  to be heated by the heating elements  28 ,  30  and  32 . The foregoing configuration avoids depositing minerals at the bottom of the reservoir  12 . 
   Hot water then flows towards the outlet conduit  18  via duct  74 . The hot water enters the outlet conduit  18  through its top end aperture  72  and downwardly flows in its channel  69 . As shown in  FIG. 7 , reservoir open end  20  and aperture  72  are adjacent and communicate via the short channel or duct  74 , this provides for there being no dead ends during water flow hence, permitting fluid flow without trapping air. 
   The thermal sensor  80  determines the temperature of the hot water and transmits this data to the controller  40 . Once the controller receives his information it will signal the triacs  64 ,  66 , and  68  to modulate the heating elements  28 ,  30  and  32  accordingly to either increase or decrease their heating temperature. Hence, triac  64  modulates the current sent to heating element  28 , triac  66  modulates the current sent to heating element  30  and triac  68  modulates the current sent to heating element  32 . Therefore the heating temperature of the elements  28 ,  30  and  32  is adjusted according to the temperature of the water flowing through the auxiliary conduit  18 . Hence, the modulating triacs  64 ,  66  provide to maintain the heating temperature of the elements  28 ,  30  and  32  constant regardless of water flow. 
   The hot water is discharged from the water heater  10  though outlet aperture  78  and enters the outlet pipe. 
   The disk type thermostat  82 , which has a manual reset mechanism, allows for independent protection in the event that water temperature rises exceedingly high. The thermostat  82  is adapted to automatically disengage the electrical supply to the heating elements  28 ,  30  and  32  should this condition occur and must be manually reset before the water heater  10  is functional again. 
   When water is no longer required, shutting off the water supply arrests its flow into the fluid heater  10 . As water ceases to flow into the inlet conduit  14 , the floatable shuttle  48  will descend by gravity disengaging the switch  52 , which notifies the controller  40  to stop the heating operation. 
   If the period of non-usage is prolonged, the reservoir may be drained of any excess water remaining by removing the cap to allow water to escape from the drainage aperture  24 . 
   Therefore, fluid heater  10  according to the present invention provides for selectively heating fluid upon demand. Fluid does not need to be maintained in the reservoir  12 , it can continually flow though the heater  10  while being heated. The simple and compact configuration of the body  11  provides for the present fluid heater  10  to take up less space and to be relatively inexpensive and easy to manufacture. Furthermore, the configuration and constant flow of water through the fluid heater  10  during the heating operation minimizes the loss of energy caused by heat convection out of the reservoir  12 . 
   Having now described an embodiment of the present invention, the following is a non-limiting description of certain alternative embodiments of the present invention. 
   The reservoir  12 , inlet conduit  14 , auxiliary conduit  16  and outlet conduit  18  may be an integrated moulded piece forming the body  11 . A variety of materials may be used to make the body  11  yet, injected plastic is more convenient to make a one-piece body mould. Advantageously, engineering plastic is used. Advantageously, the material used should be able to withstand high temperatures and pressures. It is of course advantageous to use non-rusting material. Of course, the reservoir  12 , inlet conduit  14 , auxiliary conduit  16  and outlet conduit  18  may be separate pieces that are mounted together to form the body  11 . 
   The reservoir  12  may be provided in a variety of shapes and sizes known in the art. What is important is that it provides a space for water to be heated in accordance with the present invention. 
   The drainage aperture  24  may be configured to receive a reservoir temperature and pressure release valves. 
   The heating elements  28 ,  30  and  32  may be positioned within the reservoir  12  in a variety of ways known in the art. Furthermore, the heating elements  28 ,  30  and  32  need not be secured to cover  34  but may be mounted directly to the reservoir as can be contemplated by the skilled artisan. The heating elements  28 ,  30  and  32  may be provided in a number of configurations and may be of various types known in the art. What is important is that they be positioned within the reservoir  12  so as to heat the fluid in accordance with the present invention. In this example there are three heating elements, yet more or less heating elements may be provided. 
   It should be noted that when selecting the configuration of the reservoir  12  and the heating elements  28 ,  30  and  32  that increasing the contact of the fluid with the heating elements is advantageous. In the example illustrated, the configuration of reservoir  12  and its corresponding fluid-containing chamber  19  as well as the disposition and configuration of the heating elements  28 ,  30  and  32  provide for sufficient contact between the aforementioned elements and the fluid that is to be heated thus, speeding up the heating operation. 
   The inlet-conduit assembly  13  may be provided in a variety of configurations. The inlet-conduit assembly may  13  include only the inlet conduit  14  which may include both the fluid-flow detector assembly  47  and the heating element modulator  62 . In this case, the inlet conduit  14  would be in fluid communication with the reservoir  12 . 
   The inlet conduit  14  may be provided in a variety of configurations and sizes, which provide for letting fluid into the heater  10 . The bottom end  42  need not be threaded but may be provided in other configurations capable of being connected to a cold fluid supply. 
   The shuttle  48  may be provided in a variety of floatable forms. The sensor  52  may be mounted to the inlet conduit  14  in a variety of ways, which provide for magnetic contact between the shuttle magnet  50  and the sensor  52 . 
   The fluid-flow detector  47  may be a flow meter connected to the controller  40  so as to transmit data thereto. The flow meter may upon a minimum fluid flow signal the controller  40  to activate the heating elements  28 ,  30  and  32 . Furthermore, this flow data received by the controller  40  may also permit the controller to instruct the triacs  64 ,  66  and  68  to modulate the current sent to the heating elements  28 ,  30  and  32  according to fluid flow in the inlet conduit as well as the fluid temperature in the outlet conduit  18 . 
   It may be contemplated to position the fluid-flow detector assembly  47  in the outlet conduit  18  as well. 
   Of course, the skilled artisan within the scope of the present invention may contemplate other types of fluid-flow detector assemblies  47 . Furthermore, other types of flow detectors  48  and corresponding sensors  52  may be contemplated. What is important is that the fluid-flow assembly  47  used in the present invention signals the controller  40  when fluid enters the inlet conduit  14  in order for the heating operation to commence or that fluid has ceased entering the inlet conduit  14  in order to stop the heating operation. 
   The channel  56  may also be any other type of communication means between the inlet and auxiliary conduits  14  and  16  which provides for water to flow from the inlet conduit  14  to the auxiliary conduit  16 . 
   The auxiliary conduit  16  may be provided in a variety of suitable configurations and sizes. 
   Furthermore, the auxiliary conduit  16  bottom portion  58  may be in communication with the reservoir  12  via a porous wall, a plurality of apertures or a channel or any other suitable communication means. 
   In the illustrated example there are three triacs  64 ,  66  and  68  each corresponding to a respective heater element  28 ,  30  and  32 . Of course, the number of triacs will vary with the number of heating elements used. 
   It can be contemplated within the scope of the invention to use other heating element modulators  62  known to the skilled artisan. Whatever type of modulator used its function should be to modulate the temperature of the heating elements in accordance with the temperature and/or flow rate date received by the controller  40  as explained herein. 
   The outlet conduit  18  can be provided in a variety of sizes and configurations for leading heated water to hot fluid pipe. Furthermore, duct  74  is replaceable by a variety of communication means such as channels, pipes, perforated walls and the like for water to flow from the reservoir  12  to the outlet conduit  18 . The bottom end  76  need not be threaded but may be provided in other configurations capable of being connected to a hot water output. 
   As is apparent to the skilled artisan, a variety and a greater number of thermal sensors or temperature probes  80  can be mounted to the outlet conduit  18  in a variety of ways to detect the temperature of the heated water. 
   Furthermore, the thermal sensor  80  may be placed in the inlet conduit  14  as well as in the auxiliary conduit  18 ; in the latter case it should be placed near aperture  54 . A thermal sensor  80  may also be placed in the reservoir  12 . Hence, the invention may be provided with one, two, three or four thermal sensors and even a flow meter each sending data to the controller  40  for modulation of the heating operation. 
   Also, depending on the power of the water heater with respect to number of heating elements or heating capacity of the elements more than one as well as various common types of thermostats, such as  82 , may be used to disengage electrical supply as explained above. 
   The common plate  84  may be made of metal or be part of the body mould and hence, can be made of plastic. The plate  84  may be integral to the top portions of the reservoir  12 , inlet, auxiliary and outlet conduits  14 ,  16  and  18  respectively or may be a separate piece configured to join the foregoing components. Of course, the invention may be contemplated without a plate  84 . 
   The cover  34  may be made of strong durable material such as metal or plastic. Depending on the configuration and types of heating elements the cover  34  will be provided with means to either secure the heating elements thereto or to provide that the heating elements be in electrical communication with the controller  40  and/or modulator  62 . In the case where a plate  84  is not provided a plurality of covers may be contemplated for reservoir open end  20 , the inlet conduit exit-aperture  46 , the auxiliary conduit top end aperture  54 , the channel  56 , the outlet conduit top end aperture  72  and the duct  74 . 
   Enclosure  90  may be provided in a variety of shapes and sizes for enclosing the water heater  10  and allowing easy access thereto. Enclosure  90  is preferably made of plastic, metallic or any other material. Of course the invention may be contemplated without an enclosure  90 . 
   It should also be noted that power may supplied to the heating elements  28 ,  30  and  32 , the triacs  64 ,  66  and  68  and the controller  40  in a variety of ways known in the art. 
   The controller  40  may be an electronic control circuit or a programmable data processor, a computer or any type of controller known in the art for the purposes of the present invention. 
   It is to be understood that while the above description describes a generally vertical heater, one skilled in the art could design a generally horizontal heater within the scope of the present invention using alternative flow-detector assemblies of course. In this latter case the terms top and bottom for describing ends may be replaced by first and second ends. 
   It is to be understood that the invention is not limited in its application to the details of construction and parts illustrated in the accompanying drawings and described hereinabove. The invention is capable of other embodiments and of being practised in various ways. It is also to be understood that the phraseology or terminology used herein is for the purpose of description and not limitation. Hence, although the present invention has been described hereinabove by way of preferred embodiments thereof; it can be modified, without departing from the spirit, scope and nature of the subject invention as defined in the appended claims.