FIELD OF THE INVENTION

Embodiments of the invention are related to a thermostatic working element having bi-component housing. BACKGROUND

Thermostatic working elements are used in various systems, for example, in vehicles cooling systems. Such thermostatic working elements generally include a housing having a pot-shaped design, which is typically made of metal. Copper or copper alloys are commonly used to form the thermostatic working element housing since they have both good thermal conductance and high rigidity. One of the problems that often occurs while using copper or copper alloys housings for thermostatic working elements is the reaction of copper with other metals that are present in proximity to the copper. Such metals (for example, aluminum and ferrous) tend to develop corrosion when are in contact with copper. This problem is particularly relevant in the vehicle industry where the use of other metals that are damaged by the copper is currently enhanced.

There is thus a need in the art for thermostatic working elements that would allow the desired properties of thermal conductance and high rigidity, while minimizing or eliminating the corrosion problem. 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 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. There is provided herein, according to some embodiments, a thermostatic working element having a housing formed of aluminum or aluminum alloy and including a strengthening element configured to provide extra strength to the thermostatic working element. The strengthening elements may be made of stainless steel or any other material that is adapted to prevent dysfunction of the thermostatic working element. Thermostatic working elements having strengthening (reinforcing) parts are adapted to reduce or eliminate the corrosion problem discussed herein, while allowing thermal conductivity and strength (rigidity) of the housing.

According to some embodiments, the housing of the thermostatic working element has a bottom side and a top side, wherein the bottom side, optionally having the shape of a cylinder. The housing may be formed from a metal, such as aluminum, or a metal alloy, such as aluminum alloy, having high thermal conductivity (for example, 200 (W\m k) or more). The strengthening element has a high rigidity and is adapted to resist pressure created in the housing (for example, of 200 bar or more). The strengthening element may be formed from any metal or metal alloy that is adapted to provide rigidity and prevent disassembling of the thermostatic working element upon pressure increase in the housing. For example, the strengthening element may be formed from stainless-steel. According to some embodiments, the housing may have thermal conductivity higher than that of the strengthening element. According to some embodiments, the strengthening element may have rigidity higher than that of the housing. Such thermostatic working element having a housing and a separate strengthening element, each having different properties may reduce or even eliminate the corrosion problem discussed herein, while providing thermal conductivity and strength (rigidity). According to some embodiments, there is provided herein a thermostatic working element comprising: a housing formed of aluminum or aluminum alloy having a bottom side and a top side, a cap configured to close the top side and a strengthening element located adjacent to the top side and configured to provide extra strength to the thermostatic working element and to displacing of the cap (the displacing of the cap can be occurred by opening the edges of the top side of the housing).

The strengthening element may be tightened over a bent edge of the top side. The strengthening element may be tightened over a bent edge of the top side, wherein the bent edge of the top side is bent over the edge of the cap.

The strengthening element may be tightened over a bent edge of the cap, wherein the bent edge of the cap is bent over the edge of the top side. The strengthening element may be tightened over the cap and an opening of the top side of the housing.

The strengthening element may have essentially a ring shape. The strengthening element may have essentially a ring shape having lower edge extending from a wall of the ring towards the center of the ring, essentially perpendicular to the ring wall. The strengthening element may include stainless steel. The strengthening element may be made of stainless steel.

The cap may further be configured to guide a working piston in its position and to enable a movement of the working piston up and down essentially in the direction parallel to the length the housing. According to some embodiments, there is provided herein a process of manufacturing a thermostatic working element, the process comprises: closing, with a cap, a top side of a housing of a thermostatic working element, wherein the housing is formed essentially of aluminum or aluminum alloy and tightening the cap and the top side of the housing with a strengthening element to provide extra strength to the thermostatic working element and to prevent displacement of the cap.

The process may further include, prior to tightening the cap and the top side of the housing with a strengthening element, bending an edge of the top side over an edge of the cap.

The process may further include, prior to tightening the cap and the top side of the housing with a strengthening element, bending an edge of the cap over an edge of the top side.

The strengthening element may have essentially a ring shape. The strengthening element may have essentially a ring shape having lower edge extending from a wall of the ring towards the center of the ring, essentially perpendicular to the ring wall. The strengthening element may include or be comprised of stainless steel. The housing may have thermal conductivity higher than that of the strengthening element. The strengthening element may have rigidity higher than that of the housing.

According to some embodiments, the housing has thermal conductivity higher than that of the strengthening element. According to additional or alternative embodiments, the strengthening element has rigidity higher than that of the housing.

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

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.

Fig. 1 shows a cross-section of a thermostatic working element, known in the prior art;

Fig. 2 shows a cross-section of a thermostatic working element, according to some embodiments of the invention; Fig. 3 shows a cross-section of a thermostatic working element, according to some embodiments of the invention;

Fig. 4 shows a perspective view of a thermostatic working element, wherein the top element of the housing is separated from the rest of the thermostatic working element, according to some embodiments of the invention; and Fig. 5 shows a perspective view of the thermostatic working element of Fig. 4, wherein the top element of the housing is assembled, according to some embodiments of the invention. DETAILED DESCRIPTION

Known thermostatic working elements, such as thermostatic working element 100 of Fig. 1 (shown as a cross-section), generally includes a housing 102, typically made of copper or copper alloys. Housing 102 is 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. Bottom side 104 is configured to be filled with 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 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.

The top side 106 of housing 102 is wider 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. In manufacturing of thermostatic working element 100, edge 120 of top side 106 of housing 102 are bent over edge 122 of cap 116, 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.

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, which is made of copper or copper alloy, 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).

One of the problems that often occurs while using copper or copper alloys housing (such as housing 102) for thermostatic working elements (such as thermostatic working element 100) is the reaction of copper with other metals that are present in proximity to the copper. Such metals (for example, aluminum and ferrous) tend to develop corrosion when are in contact with copper. This problem is particularly relevant in the vehicle industry where there is increase use of other metals that are damaged by the copper. There is provided herein, according to some embodiments, a thermostatic working element having a housing formed of aluminum or aluminum alloy. Aluminum or aluminum alloys are known to have relatively good thermal conductance, are easy to process and do not cause a corrosion as discussed above. However, Aluminum or aluminum alloys are generally not rigid enough and often, upon pressure increase, the cap (such as cap 116 in Fig.l) may push the edge of the top side of the aluminum housing (such as edge 120 of top side 106 of housing 102 in Fig.l) and be released from its place. In such case the operation of the thermostatic working element is damaged.

Reference is now made to Fig. 2, which shows a cross-section of a thermostatic working element, according to some embodiments of the invention. Thermostatic working element 200 showed in Fig. 2 generally include a housing 202, typically made of aluminum or aluminum alloy or any other metal or alloy that essentially does not cause corrosion in adjacent metals. Housing 200 is a one-piece element which includes two sides: a bottom side 204, which is generally in the shape of a cylinder and is generally closed, and a top side 206, which is generally opened. Bottom side 204 is configured to be filled with an expansion medium 210, for example, a wax mixture which, in a temperature range which can be defined by the mixture, changes its state of aggregation and drives out a working piston 212. Working piston 212 is partially positioned within a membrane 214 (in this case a bag-type membrane) which is disposed in expansion medium 210.

The top side 206 of housing 202 is wider in diameter than bottom side 104 and is configured to be closed by a cap 216 which has a shape of a short cylinder having an edge (rim) 222 which is opening sideways (generally forming a shape of a cap or a hat). Cap 216 is configured to guide a working piston 212 in its position and to enable the movement of working piston 212 up and down (see arrow 218) in the direction parallel to the length of bottom side 204 of housing 202. In manufacturing of thermostatic working element 200, edge 220 of top side 206 of housing 202 are bent over edge 222 of cap 216, such that cap 216 is held in place and cannot be removed from its position as closing means of top side 206 of housing 202. Thermostatic working element 200 further includes strengthening element 250, optionally, having essentially a ring shape. Strengthening element 250 is positioned (tightened) over the bent edge 220 of top side 206 which are bent over edge 222 of cap 216. Strengthening element 250 is configured to provide extra strength to thermostatic working element 200 and to prevent the displacement of cap 216. Strengthening element 250 may be made of stainless steel or any other material that is adapted to prevent cap 216 from opening or displacing.

The operation of thermostatic working element 200 may be similar to the operation described for thermostatic working element 100. Thermostatic working element such as thermostatic working element 200 having a strengthening (reinforcing) element are adapted to reduce or eliminate the corrosion problem discussed herein, while allowing thermal conductivity and strength (rigidity) of the housing.

There is further provided herein, according to some embodiments, a thermostatic working element having a housing comprising at least two separate elements: a bottom element and a top element, wherein the bottom element, optionally having the shape of a cylinder, is formed from a metal, such as aluminum, or a metal alloy, such as aluminum alloy, having high thermal conductivity (for example, 200 (W\m k) or more), and wherein the top element, has a high rigidity and is adapted to resist pressure created in the housing (for example, of 200 bar or more). The top element may be formed from any metal or metal alloy that is adapted to provide rigidity and prevent disassembling of the thermostatic working element upon pressure increase in the housing. For example, the top element of the housing may be formed from stainless- steel. According to some embodiments, the bottom element may have thermal conductivity higher than that of the top element. According to some embodiments, the top element may have rigidity higher than that of the bottom element. Such thermostatic working element having a housing comprising at least two separate elements, each having different properties may reduce or even eliminate the corrosion problem discussed herein, while providing thermal conductivity and strength (rigidity). Reference is now made to Fig. 3, which shows a cross-section of a thermostatic working element, according to some embodiments of the invention.

Thermostatic working element 300 showed in Fig. 3 generally include a housing 302 which includes a bottom side 304 and a top side 306. Bottom side 304 has essentially the shape of a cylinder and is formed from a metal, such as aluminum or a metal alloy, such as aluminum alloy, having high thermal conductivity (for example, 200 (W\m k) or more. According to some embodiments bottom side 304 may be formed from any metal or alloy that essentially does not cause corrosion in adjacent metals. Bottom side 304 is generally closed at its lower part 305 and opened to top side 306 at its upper part. Top side 306 has an opening 307 which opens sideways outwardly and perpendicularly to the cylinder shape of top side 306. Opening 307 of top side 306 is configured to be closed by a cap 316. Cap 316 has a shape of a short cylinder, which is closed on one side and opened on the other side, the side that is adapted to abut opening 307. In the open side of cap 316 the edge (rim) 322 is opening sideways outwardly and perpendicularly to the cylindrical cap 316 wall (cap 316 is generally forming a shape of a cap or a hat). Edge (rim) 322 and opening 307 adjoin each other.

Thermostatic working element 300 further includes strengthening element 350, optionally, having essentially a ring shape having lower edge 308 extending from ring wall 309 towards the center of the ring, essentially perpendicular to ring wall 309.

Strengthening element 350 is configured to be tightened over cap 316 and opening 307 of top side 306.

In manufacturing of thermostatic working element 300, top side 306 of housing 302 is closed by cap 316, such that edge (rim) 322 of cap 316 abuts opening 307 of top side 306. Housing 302 via its bottom side 304 is then placed into strengthening element 350, such that opening 307 of top side 306 abuts lower edge 308 of strengthening element 350.

Strengthening element 350 is then tightened over opening 307 of top side 306 and cap 316 to form a rigid enforcement to working element 300. Strengthening element 350 is configured to prevent the displacement of cap 316. Strengthening element 350 is adapted to prevent cap 316 from displacing. Strengthening element 350 is adapted to resist pressure created in housing 302 (for example, of 200 bar or more). Strengthening element 350 may be formed from any metal or metal alloy that is adapted to provide rigidity and prevent disassembling of the thermostatic working element upon pressure increase in the housing. For example, strengthening element 350 may be formed from stainless-steel.

Housing 302 is configured to be filled with an expansion medium 310, for example, a wax mixture which, in a temperature range which can be defined by the mixture, changes its state of aggregation and drives out a working piston 312. Working piston 312 is partially positioned within a membrane 314 (in this case a bag-type membrane) which is disposed in expansion medium 310.

Cap 316 is configured to guide working piston 312 in its position (by passing through an opening in cap 316) and to enable the movement of working piston 312 up and down (see arrow 318) in the direction parallel to the length of bottom side 304 of housing 302.

The operation of thermostatic working element 300 may be similar to the operation described for thermostatic working element 100. Such thermostatic working element having a housing comprising at least two separate elements may reduce or even eliminate the corrosion problem discussed herein, while allowing thermal conductivity and strength (rigidity).

Reference is now made to Figs. 4 and 5 which clearly show the housing and strengthening element in a disassembled and assembled configuration, according to some embodiments of the invention. Fig. 4, shows a perspective view of a thermostatic working element 300' (similar to thermostatic working element 300 in Fig. 3), wherein strengthening element 350' (having ring wall 309' and lower edge 308') is shown separated from the rest of thermostatic working element 300' (for example, of housing 302'), according to some embodiments of the invention. Fig. 5 shows a perspective view of the thermostatic working element of Fig. 4, wherein strengthening element 350' is assembled and tightened over top side 306' of housing 302' and cap 316', according to some embodiments of the invention. Also shown in Figs. 4 and/or 5 are closed lower part 305' and opening 307' of top side 306' and working piston 312'. Strengthening element 350' (having ring wall 309' and lower edge 308'), housing 302', top side 306', bottom side 304', lower part 305', opening 307', cap 316' and working piston 312' are essentially similar to the corresponding strengthening element 350 (having ring wall 309 and lower edge 308), housing 302, top side 306, bottom side 304, lower part 305, upper part 307, cap 316 and working piston 312 of thermostatic working element 300 of Fig. 3.