A cartridge heater
The innovative design of cartridge heaters with longitudinal grooves and supply pins simplifies assembly, reducing production time and costs by eliminating the need for specialized labor.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- I R C A S P A IND RESISTENZE CORAZZATE E AFFINI
- Filing Date
- 2025-11-19
- Publication Date
- 2026-06-04
AI Technical Summary
Cartridge heaters require complex and time-consuming manual assembly processes, necessitating specialized labor, leading to high manufacturing costs.
The design incorporates an electrically insulating core with longitudinal grooves for housing heating elements, which are secured to supply pins, allowing easier and quicker assembly without specialized labor.
Facilitates faster, simpler, and cheaper production of cartridge heaters with reduced operational complexity and labor requirements.
Smart Images
Figure IB2025061826_04062026_PF_FP_ABST
Abstract
Description
[0001] A CARTRIDGE HEATER
[0002] Field of the invention
[0003] The present invention pertains to the field of electric heating devices. In particular, the invention relates to a type of electric heater referred to as a cartridge heater. Background art
[0004] Cartridge heaters are a type of electric heating device. Cartridge heaters comprise an electrically insulating core and one or more heating elements adapted to generate heat when electrically powered.
[0005] The electrically insulating core, also referred to as the core, is made, for example, of a ceramic material.
[0006] The heating elements are typically helical, for example they are helical wires.
[0007] To date, the electrically insulating core is made so as to have a plurality of holes where the heating elements are arranged.
[0008] The outer side surface of the electrically insulating core is substantially cylindrical.
[0009] The assembly of the heating elements with the electrically insulating core requires a considerable number of operations, which are often manual with long processing times.
[0010] In particular, the insertion of the heating elements into the holes takes a long time and specialized labor is required, capable of performing such operations.
[0011] Therefore, the costs for manufacturing a cartridge heater of the known type are generally quite high.
[0012] Thus, the need is felt to manufacture cartridge heaters more quickly and easily, without the need for particularly specialized labor.
[0013] Summary of the invention
[0014] It is an object of the present invention to provide a cartridge heater that can be made more quickly and more easily with respect to the prior art.
[0015] In particular, it is an object of the invention to provide a cartridge heater that can be made more cheaply with respect to the prior art.
[0016] The present invention achieves at least one of such objects, and other objects, which will be apparent in light of the present description, by means of a cartridge heater, according to claim 1 , comprising an electrically insulating core, or core; at least one heating element, adapted to generate heat when electrically powered; wherein the electrically insulating core has a side surface having a plurality of longitudinal grooves; wherein said at least one heating element comprises a first stretch and a second stretch, each arranged in a respective longitudinal groove of said plurality of longitudinal grooves; wherein the cartridge heater comprises a plurality of supply pins, each supply pin of which extends, partially or completely, into a respective longitudinal groove; wherein each heating element has two ends, each secured to a respective supply pin; and each longitudinal groove extends over the whole length of the core, in particular, along the longitudinal axis of the core.
[0017] Advantageously, a cartridge heater according to the invention can be made in a quicker, simpler and cheaper manner with respect to the prior art.
[0018] Advantageously, a cartridge heater according to the invention does not require specialized labor in order to be produced, and it requires a lower number of operations with respect to the prior art.
[0019] Advantageously, arranging said stretches of the heating element in the respective grooves is quick and easy, in particular, it is quicker and easier than inserting the heating element into one or more holes of the electrically insulating core, as is the case in the prior art.
[0020] Advantageously, said stretches of the heating element can be arranged in the respective longitudinal grooves by lateral insertion.
[0021] The longitudinal grooves can be produced, e.g., by milling.
[0022] Advantageously, each supply pin extends, partially or completely, into a respective longitudinal groove. Therefore, the production of the cartridge heater is simplified. In fact, as each supply pin extends into a respective longitudinal groove, each supply pin can be suitably held in position during the production of the cartridge heater. Advantageously, each longitudinal groove extends over the whole length of the core, in particular along the longitudinal axis of the core. Therefore, the production of the cartridge heater is simplified, and a complex-shaped core is not required.
[0023] Further features and advantages of the invention will become more apparent in light of the detailed description of exemplary, but non-exclusive embodiments.
[0024] The dependent claims describe particular embodiments of the invention.
[0025] Brief description of the drawings
[0026] The description of the invention refers to the accompanying drawings, which are provided by way of non-limiting example, in which:
[0027] Figure 1 shows a perspective view of a cartridge heater according to the invention; Figure 2 shows a perspective view of some components of the heater in Figure 1 ; Figure 3 shows a side view of some components of the heater in Figure 1 , during an assembly step (some components are not fully shown);
[0028] Figure 4 shows a perspective view of some components of the heater in Figure 1 , during another assembly step (some components are not fully shown);
[0029] Figure 5 shows a side view of the cartridge heater in Figure 1 ;
[0030] Figure 6 shows section A-A in Figure 5;
[0031] Figure 7 shows an exploded side view of some components of the heater in Figure 1.
[0032] The same elements or components have the same reference numerals.
[0033] Description of exemplary embodiments of the invention
[0034] With reference to the Figures, exemplary embodiments of a cartridge heater 1 are described according to the invention.
[0035] In all embodiments, the cartridge heater 1 comprises an electrically insulating core 2; and at least one heating element 3a, 3b, 3c, adapted to generate heat when electrically powered; the core 2 has a side surface 27, in particular an outer side surface, having a plurality of longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f; said at least one heating element 3a, 3b, 3c comprises a first stretch 31 and a second stretch 32 each arranged in a respective longitudinal groove 20a, 20b of said plurality of longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f; the cartridge heater 1 comprises a plurality of supply pins 4a, 4b, of which each supply pin 4a, 4b extends, in particular partially or completely, into a respective longitudinal groove 20a, 20b, 20c, 20d, 20e, 20f; each heating element 3a, 3b, 3c has two ends 38a, 38b, each secured to a respective supply pin 4a, 4b; and each longitudinal groove 20a, 20b, 20c, 20d, 20e, 20f extends over the whole length of the core 2, in particular along the longitudinal axis Y of the core 2.
[0036] In particular, each heating element 3a, 3b, 3c extends into at least two longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f, preferably into two longitudinal grooves 20a, 20b.
[0037] Each heating element 3a, 3b, 3c, in particular, comprises a third stretch 33, extending outside the longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f; in particular, said third stretch 33 extends at an axial end 29 of the core 2.
[0038] In particular, the third stretch 33 of each heating element 3a, 3b, 3c is in contact with an axial end 29 of the core 2.
[0039] The third stretch 33, in particular, extends beyond the axial end 29 of the core 2, in particular, axially beyond the axial end 29 of the core 2.
[0040] The core 2 defines a longitudinal axis Y, which, in particular, is also the longitudinal axis of the cartridge heater 1. In particular, said longitudinal axis Y is also the central axis of the core 2, preferably also of the cartridge heater 1 .
[0041] Preferably, in all embodiments, the core 2 is a substantially cylindrical body, the side surface 27 of which, in particular the outer side surface, has said plurality of longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f.
[0042] Preferably, in all embodiments, each longitudinal groove 20a, 20b, 20c, 20d, 20e, 20f, seen in section, in a plane orthogonal to the longitudinal axis Y, is substantially U-shaped. Preferably, aach longitudinal groove 20a, 20b, 20c, 20d, 20e, 20f has a respective plane of symmetry containing the longitudinal axis Y (in particular, central longitudinal) of the core 2.
[0043] In particular, the longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f extend parallel to said longitudinal axis Y. More particularly, the longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f extend mainly along said longitudinal axis Y.
[0044] In particular, the longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f are recesses. The core 2 has two ends 28, 29, or axial ends.
[0045] The core 2 can be formed by one or more electrically insulating bodies. In the example shown by way of non-limiting example, the core 2 is formed by one electrically insulating body.
[0046] The core 2 is preferably made of ceramic, in particular, refractory ceramic.
[0047] The side surface 27 of the core 2 has a plurality of longitudinal protrusions 21 a, 21 b, 21c, 21 d, 21 e, 21f, in particular protruding with respect to the longitudinal grooves. The number of longitudinal protrusions 21 a, 21 b, 21 c, 21 d, 21e, 21f is equal to the number of longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f. Between each pair of longitudinal protrusions 21 a, 21 b, 21 c, 21 d, 21 e, 21 f, there is a respective longitudinal groove 20a, 20b, 20c, 20d, 20e, 20f.
[0048] In particular, the aforesaid third stretch 33 of each heating element 3a, 3b, 3c is in contact with an axial end of the longitudinal protrusion 21 b which is present between the two longitudinal grooves 20a, 20b, in which the first stretch 31 and the second stretch 32 are arranged, respectively. In particular, said third stretch 33 substantially passes round said axial end of said longitudinal protrusion 21 b. In particular, each heating element 3a, 3b, 3c preferably extends along a respective substantially U-shaped axis.
[0049] The longitudinal grooves 20a, 20b in which said first stretch 31 and said second stretch 32 are arranged, are consecutive to one another.
[0050] In particular, each longitudinal groove 20a, 20b, 20c, 20d, 20e, 20f extends over the whole length (along said longitudinal axis Y) of the core 2.
[0051] Said first stretch 31 and said second stretch 32 are preferably helical or substantially helical, in particular so that the first stretch 31 and the second stretch 32 form a respective winding extending about a respective axis parallel to said longitudinal axis Y.
[0052] Each heating element 3a, 3b, 3c is preferably a metal wire, in particular a resistive wire.
[0053] In particular, said first stretch 31 and said second stretch 32 of metal wire are helical or substantially helical, in particular so that the first stretch 31 and the second stretch 32 of metal wire form a respective winding, extending about a respective axis, parallel to said longitudinal axis Y. As stated previously, the cartridge heater 1 comprises a plurality of supply pins 4a, 4b (only two of them are numbered in the Figures). In particular, two supply pins 4a, 4b are provided for each heating element 3a, 3b, 3c.
[0054] In particular, each supply pin 4a, 4b extends, only partially or completely, into a respective longitudinal groove 20a, 20b; and each heating element 3a, 3b, 3c has two ends 38a, 38b, each secured to a respective supply pin 4a, 4b, e.g., by welding.
[0055] In particular, one end 38a is the end of the first stretch 31 , and the other end 38b is the end of the second stretch 32.
[0056] The end 38a is arranged in the longitudinal groove 20a where the first stretch 31 is arranged, and the end 38b is arranged in the longitudinal groove 20b where the second stretch 32 is arranged.
[0057] The cartridge heater 1 comprises an outer body 6, or casing, in which the core 2 is arranged. Said at least one heating element 3a, 3b, 3c is also arranged in the outer body 6.
[0058] The longitudinal grooves 20a, 20b, 20c, 20d, 20e, 20f are filled with electrically insulating material, in particular so that said first stretch 31 and said second stretch 32 of each heating element 3a, 3b, 3c are incorporated into said electrically insulating material. In particular, each heating element 3a, 3b, 3c is incorporated, in particular completely incorporated, into the electrically insulating material. In particular, said electrically insulating material is distinct from the core 2.
[0059] The electrically insulating material is preferably magnesium oxide or comprises magnesium oxide.
[0060] In particular, the cartridge heater 1 comprises a body 5, or closing element. In particular, the body 5 closes an axial end of said outer body 6. The body 5 can, for example, be made using a sealing material.
[0061] The cartridge heater 1 preferably comprises, for at least one supply pin 4a, 4b, preferably for each supply pin 4a, 4b, a thermal fuse 42a, in particular, a respective thermal fuse 42a, and a further respective supply pin 41 a, 41 b (or second supply pin), and each further supply pin 41a, 41 b crosses said body 5. Alternatively, in a variant not shown, said supply pins 4a, 4b cross said body 5.
[0062] More particularly, in the illustrated embodiment, the supply pins 4a, 4b of each heating element 3a, 3b, 3c are inside the outer body 6. The supply pins 4a, 4b can also be referred to as first supply pins 4a, 4b. In particular, the first supply pins 4a, 4b are completely inside the outer body 6. The cartridge heater 1 also comprises a second outer supply pin 41 a, 41 b for each first supply pin 4a, 4b. The second supply pins 41 a, 41 b are preferably arranged partially inside and partially outside the outer body 6. Between each first supply pin 4a, 4b and the respective second supply pin 41 a, 41 b, a respective thermal fuse 42a is present (only one of which is numbered in Figure 6). Each first supply pin 4a, 4b is secured to a respective thermal fuse 42a, and each thermal fuse 42a is secured to a respective second supply pin 41 a, 41 b. A metal body 43a is preferably provided (only one of which is numbered in Figure 6) in which each first supply pin 4a, 4b and the respective thermal fuse 42a are at least partially arranged; and said metal body 43a secures, in particular mechanically secures, each first supply pin 4a, 4b and the respective thermal fuse 42a between one another, preferably by exerting an elastic force thereon and / or by interference, and electrically connects each first supply pin 4a, 4b and the respective thermal fuse 42a to one another. Said metal body 43a is preferably a metal cage or metal sleeve, in particular, an elastic metal cage or an elastic metal sleeve. The metal body 43a preferably has a plurality of slots or slits 431 , in particular, to give the metal body 43a elastic properties.
[0063] The securing by means of the metal body 43a is particularly advantageous, in particular, because it simplifies the production of the cartridge heater 1 when provided with at least one thermal fuse 42a. Further advantages of the fastening by means of the metal body 43a include: increased intervention reactivity of the thermal fuse, because the metal body 43a also acts as a thermal bridge; option of mounting thermal fuses with intervention temperatures lower than those usable with respect to a fastening with electric spot welding (and therefore with thermal input) between the thermal fuse and the respective supply pin; it allows constant and repetitive positioning, ensuring a uniform response of the thermal fuse intervention time; simplification of the production process; it allows assembling the thermal fuse in the final operations of the production process, consequently allowing greater flexibility in product customization; it does not require any special equipment and can also be done manually. The second supply pins 41 a, 41 b cross said body 5, or closing element. In particular, in this embodiment, the first supply pins 4a, 4b are secured indirectly to said body 5.
[0064] In a variant not shown, the supply pins 4a, 4b are arranged partially inside and partially outside the outer body 6. In such a variant, the supply pins 4a, 4b cross the body 5, and, in particular, are directly secured to the body 5.
[0065] In all embodiments, the supply pins 4a, 4b are all preferably arranged on the same side as the cartridge heater 1 .
[0066] In all embodiments, preferably, the supply pins 4a, 4b of each heating element 3a, 3b, 3c are close to, in particular at, the same axial end 28 of the core 2, they are preferably axially protruding with respect to said axial end 28 of the core 2. It is particularly preferable that the supply pins 4a, 4b are axially protruding with respect to said axial end 28 of the core 2 because, in this way, the production of the cartridge heater is simplified.
[0067] Each heating element 3a, 3b, 3c is preferably configured to generate a specific thermal power of at least 5 W / cm2, preferably from 5 to 30 W / cm2
[0068] The cartridge heater 1 preferably comprises a plurality of heating elements 3a, 3b.
[0069] In the illustrated non-limiting example, the cartridge heater 1 comprises three heating elements 3a, 3b, 3c.
[0070] Figure 3 diagrammatically shows an assembly step for producing the cartridge heater 1. In particular, the heating element 3b is elongated, in particular, by exploiting the aforesaid helical shape, for arranging the two stretches 31 , 32 thereof in the respective longitudinal grooves.
[0071] Similarly, Figure 4 diagrammatically shows another assembly step for producing the cartridge heater 1. In particular, the heating element 3c is elongated, in particular, exploiting the aforesaid helical shape, in order to arrange the two stretches 31 , 32 thereof in the respective longitudinal grooves.
[0072] Those skilled in the art, in light of the present description, are capable of appreciating that the assembly of the one or more heating elements 3a, 3b, 3c with the core 2 is particularly easy, in particular, easier than a core having longitudinal holes instead of longitudinal grooves.
Claims
CLAIMS1. A cartridge heater (1 ) comprising an electrically insulating core (2); at least one heating element (3a, 3b, 3c), adapted to generate heat when electrically powered; wherein the electrically insulating core (2) has a side surface (27) having a plurality of longitudinal grooves (20a, 20b, 20c, 20d, 20e, 20f); wherein said at least one heating element (3a, 3b, 3c) comprises a first stretch (31 ) and a second stretch (32), each arranged in a respective longitudinal groove (20a, 20b) of said plurality of longitudinal grooves (20a, 20b, 20c, 20d, 20e, 20f); wherein the cartridge heater (1 ) comprises a plurality of supply pins (4a, 4b), of which each supply pin (4a, 4b) extends, partially or completely, into a respective longitudinal groove (20a, 20b, 20c, 20d, 20e, 20f); wherein each heating element (3a, 3b, 3c) has two ends (38a, 38b), each secured to a respective supply pin (4a, 4b); and wherein each longitudinal groove (20a, 20b, 20c, 20d, 20e, 20f) extends over the whole length of the core (2), in particular, along the longitudinal axis (Y) of the core (2).
2. A cartridge heater (1 ) according to claim 1 , wherein each heating element (3a, 3b, 3c) comprises a third stretch (33) extending outside the longitudinal grooves (20a, 20b); in particular, wherein said third stretch (33) extends at an axial end (29) of the electrically insulating core (2); in particular wherein said third stretch (33) of each heating element (3a, 3b, 3c) is in contact with an axial end of a longitudinal protrusion (21 b) present between the two longitudinal grooves (20a, 20b) in which the first stretch (31 ) and the second stretch (32) are arranged, respectively.
3. A cartridge heater (1 ) according to claim 1 or 2, wherein said third stretch (33) is in contact with an axial end (29) of the electrically insulating core (2).
4. A cartridge heater (1 ) according to any one of the preceding claims, wherein the longitudinal grooves (20a, 20b) in which said first stretch (31 ) and said second stretch (32) are arranged, are consecutive to one another.
5. A cartridge heater (1 ) according to any one of the preceding claims, wherein said first stretch (31 ) and said second stretch (32) are substantially helical.
6. A cartridge heater (1 ) according to any one of the preceding claims, wherein said at least one heating element (3a, 3b, 3c) is a metal wire, in particular a resistive wire.
7. A cartridge heater (1 ) according to any one of the preceding claims, wherein the supply pins (4a, 4b) of each heating element (3a, 3b, 3c) are in proximity of, in particular at, the same axial end (28) of the core (2); preferably wherein the pins (4a, 4b) are axially protruding with respect to said axial end (28) of the core (2).
8. A cartridge heater (1 ) according to claim 7, comprising a body (5), or closing element; wherein the supply pins (4a, 4b) cross said body (5).
9. A cartridge heater (1 ) according to claim 7 comprising a body (5), or closing element; wherein the cartridge heater (1 ) comprises for at least one supply pin (4a, 4b), preferably for each supply pin (4a, 4b), a respective thermal fuse (42a) and a further respective supply pin (41 a, 41 b) and each further supply pin (41a, 41 b) crosses said body (5).
10. A cartridge heater (1 ) according to claim 9, comprising a metal body (43a) in which each supply pin (4a, 4b) and the respective thermal fuse (42a) are at least partially arranged; wherein said metal body (7) secures, in particular mechanically secures, each supply pin (4a, 4b) and the respective thermal fuse (42a) to one another, preferably by exerting an elastic force thereon and / or by interference, and electrically connects each supply pin (4a, 4b) and the respective thermal fuse (42a) to one another.
11. A cartridge heater (1 ) according to any one of the preceding claims, wherein said longitudinal grooves (20a, 20b, 20c, 20d, 20e, 20f) are filled with electrically insulating material, preferably magnesium oxide or comprising magnesium oxide, in particular so that said first stretch (31 ) and said second stretch (32) of each heating element (3a, 3b, 3c) are incorporated into said electrically insulating material; in particular wherein each heating element (3a, 3b, 3c) is incorporated into said electrically insulating material.
12. A cartridge heater (1 ) according to claim 11 , wherein said electrically insulating material is distinct from the core (2)13. A cartridge heater (1 ) according to any one of the preceding claims, comprising a plurality of heating elements (3a, 3b, 3c).
14. A cartridge heater (1 ) according to any one of the preceding claims, comprising an outer body (6), or casing, in which said electrically insulating core (2) is arranged; in particular wherein the electric heater (1 ) comprises a body (5), or closing element, which closes an axial end of said outer body (6).
15. A cartridge heater (1 ) according to any one of the preceding claims, wherein the core (2) is a substantially cylindrical body, the side surface (27) of which has said plurality of longitudinal grooves (20a, 20b, 20c, 20d, 20e, 20f).
16. A cartridge heater (1 ) according to any one of the preceding claims, wherein each longitudinal groove (20a, 20b, 20c, 20d, 20e, 20f), seen in section, in a plane orthogonal to the longitudinal axis (Y) of the core (2), is substantially U-shaped; preferably wherein each longitudinal groove (20a, 20b, 20c, 20d, 20e, 20f) has a respective plane of symmetry containing the longitudinal axis (Y) of the core (2).