Abstract:
There is provided a thermostatic working element comprising: a housing for receiving an expansion medium; an electric heating element arranged in the housing and provided with connecting lines, wherein a base of a bottom side of the housing comprises an opening for passage therethrough of the connecting lines; and a gasket disposed between the electric heating element and the base of the bottom side of the housing, essentially surrounding the opening, wherein the housing further comprises a recess located in proximity to the electric heating element, configured to press the electric heating element and the gasket against the base of the bottom side of the housing and thereby sealing of the housing is facilitated.

Description:
FIELD OF THE INVENTION 
       [0001]    Embodiments of the invention are related to a heated thermostatic working element configure to receive an electric heating element. 
       BACKGROUND 
       [0002]    Thermostatic working elements are used in various systems, for example, in vehicles&#39; cooling systems. Thermostatic working elements are used particularly with a thermostatic valve. Electrically heated thermostatic working elements are known in the prior art, for example in U.S. Pat. No. 4,685,651, in which an opening of the bottom of the housing is closed by means of a base made of plastic which surrounds the connecting lines of the heating element and through which the connecting lines are guided to the outside. The base is produced as a separate component. It is inserted from the outside into an opening of the housing having a ring shoulder with the interposition of a sealing ring and is held by means of a flanging of the outer edge of the opening. 
         [0003]    Other type of electrically heated, thermostatic working element are described, for example, in U.S. Pat. No. 5,883,365, wherein the base is injected molded into the opening of the bottom of the housing, such that the base is already mounted when it is manufactured without requiring any additional mounting operations for bringing in and adapting the base. 
         [0004]    Still, assembling the thermostatic working element, while allowing exit of connecting lines of the electric heating element and sealing of the housing against an emerging of the expansion medium, is complicated, particularly in view of the high pressure that is created in the housing during operation of the thermostat. There is thus a need in the art for simple and efficient electrically heated thermostatic working elements that could overcome these problems. 
         [0005]    The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the figures. 
       SUMMARY 
       [0006]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. 
         [0007]    Embodiments of the invention relate to a thermostatic working element comprising: 
         [0008]    a housing for receiving an expansion medium; 
         [0009]    an electric heating element having an anchoring element, wherein the electric heating element is arranged in the housing and provided with connecting lines, the base of the bottom side of the housing including an opening for passage therethrough of the connecting lines (and optionally a part of the electric heating element); and 
         [0010]    a gasket (for example, having a shape of a torus, for example an O ring) disposed between the anchoring element and the base of the bottom side of the housing, surrounding the opening, 
         [0011]    wherein the housing further includes a circumferential recess located in proximity to the top of the anchoring element, the recess is formed by applying circumferential (such as, essentially ring like) pressured which compresses the walls of the housing inwardly, thus the anchoring element and the gasket are pressed against the base of the bottom side of the housing and thereby sealing of the housing is facilitated. 
         [0012]    There is further provided herein, according to some embodiments, a process of manufacturing the electrically heated thermostatic working element. The process may include: 
         [0013]    inserting to a housing of an electrically heated thermostatic working element a gasket and an electric heating element having anchoring element 
         [0014]    forming a circumferential recess in a wall of the housing, in proximity to the location of the top of the anchoring element inside the housing, thereby pushing the wall of the housing inwardly, pressing the anchoring element and the gasket against the base at the bottom of the housing and thereby facilitating the sealing of the housing; 
         [0015]    inserting to a housing an expansion medium, and a membrane for receiving a working piston. 
         [0016]    According to some embodiments, there is provided a thermostatic working element comprising: a housing for receiving an expansion medium; an electric heating element arranged in the housing and optionally provided with connecting lines, wherein a base of a bottom side of the housing comprises an opening for passage therethrough of the connecting lines; and a gasket disposed between the electric heating element and the base of the bottom side of the housing, essentially surrounding the opening, wherein the housing further comprises a recess located in proximity to the electric heating element, configured to press the electric heating element and the gasket against the base of the bottom side of the housing and thereby sealing of the housing is facilitated. 
         [0017]    According to some embodiments, the electric heating element comprises an anchoring element configured to stabilize the electric heating element within the housing and to prevent the pulling thereof out of the opening, wherein the gasket is disposed between the anchoring element and the base of the bottom side of the housing, surrounding the opening, and wherein the recess is located in proximity to the top of the anchoring element, configured to press the anchoring element and the gasket against the base of the bottom side of the housing. 
         [0018]    According to some embodiments, there is provided a process of manufacturing an electrically heated thermostatic working element, the process comprising: inserting to a housing of an electrically heated thermostatic working element a gasket and an electric heating element; forming a recess in a wall of the housing, in proximity to the location of the electric heating element inside the housing, thereby pushing the wall of the housing inwardly, pressing the electric heating element and the gasket against the base at the bottom of the housing and thereby facilitating the sealing of the housing. 
         [0019]    According to some embodiments, the electric heating element comprises an anchoring element configured to stabilize the electric heating element within the housing and to prevent the pulling thereof out of the opening, wherein forming the circumferential recess in the wall of the housing, is performed in proximity to the location of the top of the anchoring element inside the housing, thereby pushing the wall of the housing inwardly, pressing the anchoring element and the gasket against the base at the bottom of the housing and thereby facilitating the sealing of the housing. 
         [0020]    According to some embodiments, the process further comprising inserting to the housing an expansion medium, and a membrane configured to receive a working piston. According to some embodiments, the process further comprising covering with a cap a top side of the housing and bending the edge of the top side of the housing over the edge of the cap or bending the edge of the cap over the edge of the top side of the housing. 
         [0021]    According to some embodiments, the anchoring element is an integral part of the electric heating element. According to some embodiments, the anchoring element and the electric heating element are separately formed. 
         [0022]    According to some embodiments, the recess is a circumferential recess. According to some embodiments, the recess is formed by applying circumferential (such as, essentially ring like) pressure which compresses the walls of the housing inwardly. 
         [0023]    According to some embodiments, the gasket has essentially a shape of a torus. According to some embodiments, the gasket is an O ring. 
         [0024]    According to some embodiments, the opening is configured for passage therethrough of the connecting lines and optionally a part of the electric heating element. 
         [0025]    In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0026]    Exemplary embodiments are illustrated in referenced figures. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. The figures are listed below. 
           [0027]      FIG. 1  shows a cross-section of a thermostatic working element, according to some embodiments of the invention; and 
           [0028]      FIG. 2  shows a cross-section of the thermostatic working element of  FIG. 1 , according to some embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Reference is now made to  FIG. 1 , which shows a cross-section of a thermostatic working element and to  FIG. 2 , which shows a cross-section of the thermostatic working element of  FIG. 1 , according to some embodiments of the invention. 
         [0030]      FIGS. 1 and 2  illustrate cross-sections of the thermostatic working element  100  in a first stage configuration (assembled) and in a second stage configuration (tightened) respectively. Thermostatic working element  100  generally includes a housing  102 , typically made of a heat conductive metal such as copper, aluminum or various metal alloys. Housing  102  is shown herein to be a one-piece element which includes two sides: a bottom side  104 , which is generally in the shape of a cylinder and is generally closed, and a top side  106 , which is generally opened. 
         [0031]    It is noted herein that the scope of this disclosure also covers the bi-component housing as described in a concurrently filed USP application by the same applicant and which is entitled: “Thermostatic working element” and which is enclosed herein as reference in its entirety. 
         [0032]    Housing  102  is configured to accommodate an expansion medium  110 , for example, a wax mixture which, in a temperature range which can be defined by the mixture, changes its volume and drives out a working piston  112 . Working piston  112  is partially positioned within a membrane  114  (in this case a bag-type membrane) which is disposed in expansion medium  110 . It is noted that other configurations of a membrane (such as a disc shape membrane) are also covered under the scope of this disclosure, in which case the expansion of expending medium  110  directly drives out working piston  112 . According to some embodiments, expansion medium  110  may be divided into two parts  110   a  and  110   b.    
         [0033]    The top side  106  of housing  102  may be wider (however, not necessarily) in diameter than bottom side  104  and is configured to be closed by a cap  116  which has a shape of a short cylinder having an edge (rim)  122  which is opening sideways (generally forming a shape of a cap or a hat). Cap  116  is also configured to guide a working piston  112  in its position and to enable the movement of working piston  112  up and down (see arrow  118 ) in the direction parallel to the length of bottom side  104  of housing  102 . 
         [0034]    In operation, when the temperature increases (exceeds a predetermined value) in proximity to housing  102  of thermostatic working element  100 , heat is conducted by housing  102  to expansion medium  110 . Expansion medium  110  expends, presses against membrane  114  and pushes working piston  112  out (for example, in order to open a valve). 
         [0035]    In manufacturing of thermostatic working element  100 , edge  120  of top side  106  of housing  102  (shown in  FIG. 1  to be parallel to the length of bottom side  104 ) are bent over edge  122  of cap  116  (as shown in  FIG. 2 ), such that cap  116  is held in place and cannot be removed from its position as closing means of top side  106  of housing  102 . 
         [0036]    Electric heating element  130  is arranged inside housing  102  such that it is positioned in expansion medium  110  (for example in a bottom part of expansion medium  110 ,  110   b ) and partially extending outside of housing  102  through a (bottom) opening  140  in a base  103  of bottom side  104 . 
         [0037]    Two connecting lines  170  are connected to electric heating element  130  and are guided to the outside through opening  140  in base  103  of bottom side  104  of housing  102 . 
         [0038]    Electric heating element  130  may include (or be connected to or formed with) an anchoring element  132  which is configured to stabilize the electric heating element within housing  102 , prevent its pulling out of opening  140  and assist in sealing housing  102  against an emerging of the expansion medium. Anchoring element  132  extends from the bottom of the expansion medium  110  (shown herein as bottom part  110   b  of expansion medium  110 ) to base  103 , forming first circumferential space  131  ( FIG. 1 ) between the bottom of anchoring element  132 , the edges of base  103  and the bottom part of the walls of bottom side  104  (for the positioning of gasket  150 , see below). First circumferential space  131  (as shown in  FIG. 1 ) has a triangular cross section (but can have any other shape, such as circular, elliptic, etc.) created between the bottom of anchoring element  132 , the edges of base  103 , and the bottom part of the walls of bottom side  104  of housing  102 . 
         [0039]    Anchoring element  132  further forms a second circumferential space  133  (as shown in  FIG. 1 ) between the top of anchoring element  132 , the bottom of the expansion medium  110  (shown herein as bottom part  110   b  of expansion medium  110 ) and the wall of bottom side  104  (in proximity to the connection between the top of anchoring element  132  and the bottom of the expansion medium  110 ). Second circumferential space  133  (as shown in  FIG. 1 ) has a triangular cross section created between the top of anchoring element  132 , the bottom of the expansion medium  110  (shown herein as bottom part  110   b  of expansion medium  110 ) and the wall of bottom side  104 . 
         [0040]    Housing  102  includes a gasket  150 , generally having a shape of a torus and may from an elastic material (for example an O ring). Gasket  150  is positioned between anchoring element  132  and base  103  of bottom side  104 , surrounding opening  140 . As discussed above, there may still be a problem of sealing the housing which has received the electric heating element against an emerging of the expansion medium, particularly in high pressures. Thus, to solve this problem, according to embodiments of the invention, bottom side  104  of housing  102  further includes a recess  160 , which is an essentially circumferential recess located in proximity to the connection between the top of anchoring element  132  and the bottom of the expansion medium  110 . Recess  160  pushes the walls of bottom side  104  (in proximity to the connection between the top of anchoring element  132  and the bottom of the expansion medium  110 ) inwardly towards the center of the cylinder, such that second circumferential space  133  is minimized (as shown in  FIG. 2 ). As also shown in  FIG. 2 , recess  160  presses anchoring element  132  against base  103 , minimizes the first circumferential space  131 , presses gasket  150  and seals housing  102 . 
         [0041]    The electrically heated thermostatic working element structure as disclosed herein, according to embodiments of the invention, allows the insertion of an electric heating element to the housing and the sealing of the housing against an emerging of the expansion medium in high pressures, while allowing the exit of connecting lines. 
         [0042]    Furthermore, the process for the manufacturing of the electrically heated thermostatic working element structure, according to embodiments of the invention, is simple and does not require complicated sealing processes such as injection molding. According to embodiments, the process of manufacturing the electrically heated thermostatic working element structure may include: 
         [0043]    insertion of gasket  150  and electric heating element  130  having anchoring element  132  (for example, through opened top side  106 ) to housing  102 ; 
         [0044]    forming recess  106  (as shown in  FIG. 2 ); 
         [0045]    insertion of expansion medium  110 ; membrane  114  and working piston  112 ; 
         [0046]    covering top side  106  of housing  102  with cap  116 ; and 
         [0047]    bending edge  120  of top side  106  of housing  102  over edge  122  of cap  116  (as shown in  FIG. 2 ).