JPH0381279B2 - - Google Patents

Description

Claim 1: An automatic temperature control function comprising a thin and elongated strip-shaped ferromagnetic main layer and a strip-shaped low-resistance conductive layer laminated so as to be in thermal and electrical contact with the ferromagnetic layer. a flat and elongated flexible band-shaped heater; a locking device that tightens and fixes the band-shaped heater around a heated object; means for passing an alternating current sufficient to raise the current to . 2. A heater as claimed in claim 1, comprising a plurality of parallel elongate strips through which the current is passed, the ends of which are electrically connected to increase the length of the current flow section. 3. A heater according to claim 1 or claim 2, wherein the elongated strip has a thin covering layer made of an electrically conductive material on one of its elongated flat surfaces. 4. The thin coating layer has a plurality of substantially parallel elongated slots extending in a direction transverse to the longitudinal direction of the band-shaped heater and arranged on at least one surface of the band-shaped heater. Heater listed. 5. The heater according to claim 1, wherein the means for passing the current is means for connecting a constant alternating current between the electrical connection portions at both ends of the band-shaped heater. 6. The device according to claim 1 or 5, wherein the locking device means is a locking device that tightly tightens the band-shaped heater around the heated object and holds the band-shaped heater in a tightened state. heater. 7. The heater according to claim 6, further comprising means for tightening the band-shaped heater during the heating period so as to maintain the tension of the band-shaped heater during the heating period of the heated object. 8. The heater according to claim 7, wherein the tightening means also serves as means for passing the current through the band-shaped heater. 9 The tightening means grips one end of the band-shaped heater extending outward from the circular arc portion of the band-shaped heater wrapped around the object to be heated, and tightens the one end of the band-shaped heater to the 8. The heater according to claim 7, further comprising means for moving the heater relative to the arcuate portion, and wherein the means for gripping includes means for passing an electric current through the band-shaped heater. 10 1 of the elongated flat surface of the above band-shaped heater
2. The heater according to claim 1, wherein said band-shaped heater has a coating for physically protecting said band-shaped heater from wear. 11. The heater of claim 1, wherein the elongate member has a thin coating layer on one elongate planar surface thereof made of a material having a lower resistance than at least the first ferromagnetic material. 12. The heater according to claim 1 or 11, wherein the means for passing the current is means for inductively generating the current in the band-shaped heater. 13. The heater according to claim 4, wherein a solder layer is formed on one surface of the thin coating layer that is to be brought into contact with the object to be heated. 14. The heater according to claim 11, wherein a solder layer is formed on one surface of the thin coating layer that is to be brought into contact with the object to be heated. 15. The heater according to claim 6, comprising a tightening mechanism capable of initially tightening the band-shaped heater wound around the heated object and further tightening the band-shaped heater during the heating period. 16 Claim 1, wherein the tightening mechanism includes means for passing the current through the band-shaped heater.
The heater described in item 5. 17. The heater of claim 1 or claim 2, wherein said elongated member has a coating layer on one elongated flat surface thereof made of a material to which solder does not adhere. 18. The heater according to claim 17, wherein the coating layer is electrically conductive. 19 A flat, flat magnet having an automatic temperature control function, comprising a thin and elongated strip-shaped ferromagnetic material layer, and a strip-shaped low-resistance conductive layer laminated so as to be in thermal and electrical contact with the ferromagnetic material layer. a step of tightly wrapping and fixing an elongated flexible band-shaped heater around the object to be heated; a step of passing a current through the band-shaped heater; A method for heating an object to be heated, which comprises: a step for maintaining tension; and a step for maintaining tension. 20 Claim 1 in which the value of the current is constant
Heating method according to item 9. 21 A method of soldering one article and another article, comprising the steps of partially overlapping the articles, a thin and elongated ferromagnetic layer around both articles, and a ferromagnetic Both articles are wrapped tightly around a flat, elongated, flexible, band-shaped heater having a self-temperature regulating function and having a strip-shaped, low-resistance conductor layer laminated to make thermal and electrical contact with the body layer. A soldering method comprising the following steps: fixing the band-shaped heater, passing current through the band-shaped heater to cause it to generate heat, and supplying solder to the overlapping area of the two articles. 22. The soldering method according to claim 21, wherein the outer article of the stacked articles is compressible, and includes the step of compressing the outer article into contact with the inner article. 23 The outer article is porous, and the inner surface of the band-shaped heater is provided with solder, and the band-shaped heater heats the solder, thereby transferring the melted solder to the porous member. Claim 2 including the step of infiltrating the
Soldering method described in Section 2. BACKGROUND ART The present invention relates to an electric heater having a self-adjusting function and a method of using the same, and more specifically, the present invention relates to an electric heater having a self-adjusting function and a method of using the same, and more specifically, it uses a ferromagnetic material that is temporarily placed around a place to be heated or soldered. This invention relates to a small-sized electric heater with automatic adjustment function. This heater may be of such a form that it becomes part of the structure of the object to be heated and permanently integrated with it after the heating operation is completed, or it may It is also possible to use a configuration that can be removed from the object to be heated and then reused. U.S. Patent No. 1 for Carter and Krumme's invention
No. 4256945 describes an electric heater with temperature control function having a laminated structure, in which one thin plate layer has high magnetic permeability and high resistance value, and the other thin plate layer has a non-conductive layer. It is made of a magnetic, low resistance material (eg copper) and is in electrical and also thermal contact with the first laminate layer. The heater having the above structure is used by being connected to a constant current AC power source so that each layer is parallel to the power source. The current in that case was initially based on the skin effect;
concentrated in the high magnetic permeability and high resistance layer,
The formula P=KR ₁ holds true. Here P is power, K is
I ² or constant, and R is the effective resistance of the magnetically permeable material under densely concentrated current conditions. The resulting power consumption heats the layer until it reaches the Curie temperature. The magnetic permeability of the above layer is
Near its Curie temperature, the permeability decreases to the level of the second layer, such as copper. At that time, due to the magnetic properties of the first layer, the current is no longer confined only to the high resistance first layer, but also spreads to the copper layer, thereby The resistance to said current is substantially reduced.
The power consumed P=KR ₂ (where R ₂ << _{R 1} ) is therefore significantly reduced and the heating effect is reduced to a level such that the heater is maintained at or near the Curie temperature. Therefore, this heater performs an automatic temperature adjustment function within a narrow temperature range around the Curie temperature. The power source used in the US patented heater is typically a high frequency power source, such as 8 to 20 MHz, and by using such a high frequency, the current flows through the magnetic layer. Until the Curie temperature is reached, the magnetic layer is confined within the thin, high-resistivity magnetic layer. In particular, the thickness of the magnetic layer is determined by the degree of penetration (skin) at the operating frequency.
The maximum adjustment function can be obtained when the height is approximately 100 mm. This is because under such conditions, the maximum change in the effective resistance of the heater at or near the Curie temperature can be obtained. This fact can be explained by reference to the following equation for the degree of penetration in a magnetic material that is not a homogeneous material, ie a laminated structure. That is, the degree of penetration

where ρ is the resistivity of the material in Ωcm, μ is the relative permeability, and f is the frequency of the current. The area through which current flows decreases according to e ^-x . Here x is [thickness/
This is a numerical value expressed by [degree of penetration]. Therefore, in a highly permeable material with a uniform structure, calculations show that the current
63.2% is equal to the penetration degree (i.e. 1 times the penetration degree)
Concentrate on the area. Currie temperature range, i.e. μ=1
In the case, the current is

Spreads over the area of [formula]. Therefore, if the value of μ at room temperature is 200 (this value is 200
It can vary within the range ~1000. ), the degree of penetration in the Curie temperature region increases by the square root of 200. That is, the degree of penetration in a material with a uniform structure is 14.14 times that in the case of μ=200. The same explanation based on the skin effect can be applied to the two-layer laminated structure in the heater disclosed in the US patent. That is, when the thickness of the magnetic layer is nominally equal to the penetration depth, most of the current flows through the magnetic layer below the Curie temperature. In the Curie temperature range, most of the current flows through the copper layer, so the resistance is significantly reduced. If the thickness of the material with this high value of μ is greater than twice the penetration depth, the percentage change in current flowing through the highly conductive copper section will be small and the change in resistivity will be less pronounced. Probably not. Similarly, if the thickness of the high μ material is substantially less than the penetration depth, the percentage of current flowing through the portion of high resistivity material below the Curie temperature will be small and therefore The change in resistance also does not seem to be significant. Therefore, it is desirable that the thickness of the material with a high value of μ be in the range of about 1.0 to 1.8 times the degree of penetration. Therefore, the exact relational expression in the case of a two-layer laminated structure as described above is extremely complicated. The basic mathematical formula for surface impedance to derive the expression for the ratio of [maximum resistance Rmax below the Curie temperature] to [minimum resistance Rmin above the Curie temperature] can be found in the well-established reference “Fields and
“Waves in Communications Electronics” (Part 3)
Edition: S. Ramo, JR Whinnery, T. VanDuzer:
Published by John Wiley and Sons: New York 1965
(2013), pp. 298-303, Section 5.19.
The theory described in this reference applies strictly to flat laminates, but for all applications where the degree of penetration is substantially smaller than its radius of curvature. is also sufficiently accurate. However, in such a heater, a troublesome situation arises when the Curie temperature is reached, since the current and/or magnetic flux diffuses into the outer peripheral surface area of the heater. This especially occurs when the heater is placed near sensitive electronic components. U.S. Patent Application No. 243,777, filed March 16, 1981 by Carter and Krumme, is a partial successor to the aforementioned U.S. patented heater application; A mechanism is described for preventing high-frequency electromagnetic waves generated from a heater from being radiated into the vicinity of the heater. Such effects can be achieved by making the thickness of copper or other materials with high conductivity large enough to be several times as intrusive to the mains frequency to prevent such radiation and electric field effects. achieved by. This configuration is important in many application fields of the above-mentioned heater.
For example, in the case of a soldering iron, this is extremely significant in preventing the occurrence of a situation where the electromagnetic field causes a relatively large current in a highly sensitive circuit component, which could destroy the component. . As mentioned above, the magnetic field in a simple heater with a single layer structure, that is, a uniform structure, decreases as e ^-x , and therefore, the magnetic field reaches its maximum at a position three times the penetration depth. The magnetic field is 4.9% of the maximum area, 0.67% at the position of 5 times the penetration degree, and 0.005% of the maximum area at the position of 10 times the penetration degree. For some applications, a thickness of at least 5 times the degree of penetration is desirable, but in many applications a thickness of 3 times the degree of penetration is sufficient, and for some very sensitive instruments. If large heating currents are used in close proximity, a thickness of 10 times the penetration depth or more may be required. Although the heater of the above-mentioned US patent and the heater according to the above-mentioned US patent application can be used for the desired purpose by being connected to a suitable power source, their drawback, however, is the high cost of the high-frequency power supply. If only very low electromagnetic fields are allowed to be produced by the device, the power supply frequency must be kept very high, for example in the megahertz range, and the thickness of the copper or other non-magnetic material must be sufficiently thick. There is. Accordingly, in the invention entitled "Electrically Shielded Heater with Temperature Control Function" filed for a US patent on September 30, 1982 by J.F. The use of a layer of a non-magnetic, temperature-controlled material, usually of low resistance, makes it possible to use a constant current source of relatively low frequency.
The heater includes a first layer of high magnetic permeability and high resistance material adjacent to the current return path;
a second layer spaced apart from the current return path and comprising a material of high magnetic permeability, preferably low resistance, and having a higher Curie temperature than the first layer. Here, "high magnetic permeability" refers to a material that has a larger magnetic permeability than a paramagnetic material, that is, a ferromagnetic material, and among these, in most application fields, the magnetic permeability is 100 or higher. The above is desirable. The operating principle underlying the invention described in the above-mentioned U.S. patent application dated September 30, 1982 is that by using a high magnetic permeability and high Curie temperature material as the low resistance material layer, the current in this second layer is The degree of penetration of
Even at low frequencies, it is possible to confine electrical and Magnetically, it essentially makes it possible to be insulated or shielded. The second layer is preferably made of a low resistance material, although this is not necessarily an essential requirement. In one example of the heater using two high permeability thin plate layers, one layer is made of alloy 42 with a resistivity of about 70 to 80 μΩcm, a magnetic permeability of about 200, and a Curie temperature of about 300°C. (A ferromagnetic alloy consisting of 42% Ni and 58% Fe. Because the Ni content is 42%, it is called "Alloy 42" and is well known among those skilled in the art.) It will be done. In addition, the second layer has a resistivity of approximately 10 μΩcm and a magnetic permeability of approximately
1000, carbon steel with a Curie temperature of approximately 760°C is used. Penetration degree is Alloy 42 when using 60Hz power supply
0.1″ (inch) for carbon steel and 0.025″ for carbon steel. Practical 60Hz according to the above invention
An example of a heater is a 0.25 inch diameter cylindrical or tubular copper conductor (the "return conductor") and a thin insulating layer (often 0.002 mm).
inch thick) and a temperature-dependent magnetic alloy with a permeability of 400 and a thickness of 0.1 inch, and finally a permeability of 1000
with an external jacket of 0.1 inch thick steel;
A coaxial structure heater is used. The overall diameter of this heater is approximately 0.65 inch. For example, to prevent liquid from freezing, a heater with a total length of 1000
If the above heater were to be used in a situation where a foot heater is required, the resistance value of this heater would be 1.96Ω. At a temperature somewhat lower than the Curie temperature of the temperature-dependent magnetic alloy provided inside the outer pipe, the current at this time is 50A and the voltage at the power supply terminal is 140V. If the electrical resistance changes substantially due to a change in thermal load, the voltage required to maintain a constant current must be changed. Even in such a case, current can be supplied at a cost that is sufficiently lower than that of a constant current power supply of 8MHz to 20MHz. Therefore, the autoregulation power ratio (AR) in the heater described in the above patent application is
ratio] ranges from 2:1 to 4:1, which is not as high as in the heater according to the patented invention. This is due to the difference in resistivity being approximately 10:1, but this difference in self-adjusting power ratio is due to the fact that a high resistance material is used as a material with a low Curie temperature, and a material with a high resistance value is used as a material with a high Curie temperature. can be reduced by using lower resistivity materials, respectively. Also, the use of high permeability, relatively low resistivity materials, such as iron or low carbon steel, can further increase the power regulation ratio. The invention described in U.S. patent application Ser. It is configured to maintain an automatically adjusted power ratio of 6:1 to 7:1. Such object of the invention is disclosed in U.S. patent application Ser.
This is achieved by providing a highly conductive region at the interface between two highly permeable members. The material provided in the interface region may be, for example, copper or other highly conductive material. This material may be provided as separate layers that are not fixed in a sandwich pattern such as "magnetic material/non-magnetic material/magnetic material", or a ferromagnetic layer with a high Curie temperature and a ferromagnetic layer with a low Curie temperature. It may be provided in such a manner that it is fixed to one or both of the two ferromagnetic layers so that a low-resistance boundary region is formed at the interface between the two ferromagnetic layers. Typical thicknesses for a sanderch structure such as those described above are 0.03 inches each for both the high-Kyrie temperature ferromagnetic material and the low-Kyrie temperature ferromagnetic material at 1 KHz. To explain its operation, when the Curie temperature of the first layer is approached, its magnetic permeability decreases rapidly, and the current spreads to the copper layer.
Then, it further spreads to the second magnetic layer. The overall resistance of the structure drops rapidly due to the presence of the copper layer, resulting in a high self-adjustment ratio. Furthermore, most of the current is localized to the copper layer, with only a small percentage penetrating into the second magnetic layer. As a result, a complete shielding effect of the heater can be achieved by making this latter layer only three to five times as thick as the penetration depth. The objective of obtaining a large self-adjusting power ratio in a relatively small heater using a low frequency power supply is thus also achieved. The low frequency used here is
Although it refers to a frequency within the range of 50Hz to 10,000Hz, a frequency of 50Hz to 8,000Hz is more suitable for achieving the purpose of the invention. If the automatic adjustment ratio is 6:1 or 7:1,
The variation in the amount of heating below and above the Curie temperature is extremely large, allowing this heater to respond quickly to variations in heat load, allowing precise temperature control despite being a small heater operating at a low frequency. shall be maintained. In all of the above cases, the structure of the self-regulating heater described above is of a rigid and unbendable structure, and constitutes all or part of the device to be heated, that is, the object to be heated, and therefore It was to become part of the final structure. The above-mentioned rigid structure of conventional devices, as well as the fact that they are unavoidably part of the object to be heated, have been factors that have prevented these heaters from being used in certain fields. SUMMARY OF THE INVENTION According to the present invention, there is provided an automatically adjustable heater using the heating technology of the pending or patented heater, and a method of using the same, the heater having flexibility, It does not necessarily become part of the final structure of the heated object. More specifically, there are many cases in which it is desirable to use a flexible heater that has a self-adjusting function that allows heating without overheating, and at the same time can tightly hold the object to be heated. A typical example of such an application is in the field of shielded communication cables. In many applications of this type of cable, it may be necessary to solder a ground wire to the braided shield wire of the cable. During such soldering work, there are approximately 15% of cases in which the cable is damaged due to overheating of the insulator between the braided shield wire and the internal conductor. When the heater according to the present invention is used in such a situation, the grounding point and the solder are wound and fixed around the shield wire, and then the solder and the shield wire are connected to the melting point of the solder used. It is heated to a specific, well-controlled temperature above and below the temperature at which the insulator melts or breaks.
In this case, a band-shaped heater holds the solder and shielded wire firmly during the entire operation, thereby preventing the solder from cooling prematurely and causing an incomplete bond, and also insulating the cable. Prevent your body from overheating. A very important example of another application for flexible attachable heaters is in the melting of plastics. In addition, there are other cases where it is important or beneficial to hold the heated body in a fixed position and to provide controlled heating of the heated body, such as when connecting cables, such as when installing conduit couplings. Examples include cases in which a band-shaped shielded wire is connected to perform spot heating, and cases in which the above-mentioned band-shaped heater is attached around a frozen pipe and heated to warm it, and then removed. In one preferred embodiment of the heater according to the invention, a flexible band heater is formed of a plurality of thin flexible layers, where the insulating outer layer , a first copper layer, and a second copper layer.
An insulating layer made of a ferromagnetic material, and a second copper layer in contact with the ferromagnetic layer are laminated in the above order. The first mentioned copper layer is connected to the other copper layer at one end of the band heater, and at the other end of the band heater the two copper layers are connected to each other at the desired constant current. Connected to AC power. Attached to the end of the band heater opposite the side connected to the power supply is a closure member, in one form a plastic ball attached to a tapered hood. The other end of the band-shaped heater is configured to be easy to insert but difficult to pull out. As a result, the band-shaped heater is wrapped and fixed around the desired member to be heated. A layer of solder or similar material may be adhered to the inner copper layer of the band-shaped heater, or may be integrally provided with the inner copper layer of the band-shaped heater. Alternatively, a separate ribbon-shaped solder may be prepared and wrapped around the object to be heated. In either case, the ribbon of solder or the band-shaped heater integrally attached with solder is placed at a desired position on the object to be heated, and the second copper layer of the band-shaped heater is attached to the ribbon-shaped heater. It can be attached in contact with solder. Band-shaped heaters that heat inductively are also used. In such embodiments, the high permeability layer is covered on its outer surface by an insulating layer. Such a stack is provided with a locking device modified to form a short-circuited return path, the inner surface of which is coated with solder. A tool is provided for tightly tightening and attaching the flexible induction heating wrap around the band-shaped heater. A constant current of a relatively high frequency is supplied to the induction heating wrapped body, so that a large current is generated by induction in the high magnetic permeability material of the band-shaped heater. As the Curie temperature approaches, the value of the magnetic permeability of the ferromagnetic material approaches 1, and the current flowing through the band heater moves inward, thereby reducing the resistance of the band heater. If the layer of insulating material is very thin, a substantially integral coupling between the band-shaped heater and the wound body is achieved, and even if the permeability of the ferromagnetic layer changes, the band-shaped The current in the heater remains substantially constant. If the insulating layer is relatively thick, no integral coupling is obtained, and when the permeability decreases the induced current does not remain constant, but decreases somewhat, increasing the self-adjustment ratio. There are two forms of any of the devices mentioned above. In one form, the heater is considered a disposable item and is left on the heated object after use. In this embodiment, a layer of solder is provided on the outer surface of the second copper layer so that the band heater is soldered to the final product. In another embodiment of the invention, the inner surface of the copper layer is coated with a very thin layer of plastic that melts at high temperatures, so that the inner surface of the copper layer is free from solder. It is designed to be easily removed without contact. In any of the above embodiments, the function of the band-shaped heater during the actual soldering period is the same. Taking the case of a cable having a braided shield wire as an example again, a ground wire is inserted between the fibers of the braided shield wire, and a thin piece of solder is placed on the insertion point. After that, the above-mentioned band-shaped heater is attached, and this is tightened using, for example, a "Panduit (registered trademark)" tool, which will be described later.
An electric current is passed through the band-shaped heater to melt the solder. At this time, if necessary, tighten the band heater further using the Panduit tool to ensure that the braided shield wire, ground wire, band heater, and solder are all firmly secured during the bonding process. and be maintained. After cooling,
The band-shaped heater may be left in place or removed depending on its form. Regardless of the form of the band heater used,
Tools bearing the registered trademark "Panduit" (manufactured by Panduit Corporation, Finlay Park, Illinois). US Patent RE.26492,
3254680 and 3661187] can be modified by attaching insulators at appropriate positions so that current is supplied only to appropriate positions of the band heater. By such modification, when the tool is attached to the band-shaped heater and operated to tighten it, the tool meshes with the band-shaped heater at an appropriate position so that it becomes an electrode and comes into contact with the band-shaped heater. Current can be supplied to the band heater as needed. The advantage of the above-described system is that the band-shaped heater is maintained in a tight tension regardless of changes in the dimensions of the heated object during the heating cycle due to melting of solder or fluctuations in each component. This means that movement of the member is prevented. If this is not the case, a half-finished solder connection will be made and a complete connection will be impossible. Furthermore,
What is extremely important is that the above-mentioned band-shaped heater is equipped with an automatic temperature adjustment function.
The advantage is that there is no damage to the cable insulation. Another flexible self-regulating heater according to the present invention
One advantage relates to impedance matching with the power band heater. In conventional equipment, the length of the load circuit is extremely short;
It was about 1 to 2 inches at most. In the self-regulating heater of the present invention, the circuit is much longer, at least 3 inches or more, and even though the resistance is significantly reduced in the Curie temperature range. Impedance is to be maintained moderately. As an example, if a grounded band heater is attached to a 1-inch cable, the total length of the heater in the circuit in one embodiment is 2πD, and one end of two parallel strips are connected together. In the U-shaped embodiment shown, the diameter of the member to be heated multiplied by the number of parallel strips and π, i.e.
XπD (where X is the number of parallel strips). The pipe joint and heater assembled by conventional equipment are on the order of two inches long, or the axial length of the joint. in this way,
In the device according to the invention, the resistance varies significantly as in the conventional device, but does not drop to low values, so that impedance matching is no longer an important issue. . The band-shaped heater according to the present invention has yet another function, and if the band-shaped heater ultimately becomes a part of the structure of the object to be heated, this substantially increases the strength of the structure. It has the function of increasing For example, when the ends of two cables are connected and their braided shielded wires are partially overlapped, the band-shaped heater according to the present invention is placed over the region where the braided shielded wires are overlapped. It maintains a strong inward force and reinforces the structure. Similarly, when a braided shielded wire is attached to the outer shell of the connector, the band-shaped heater maintains a strong inward force against the braided shielded wire to fix it to the connector. It is. Such force is added separately from the strength of the solder bond. Note that the band-shaped heater according to the present invention is not necessarily used only with solder, and its use with solder is only one common example of the field of application of the band-shaped heater. Band heaters can be used to heat adhesives, mastics, fluxes, plastics, or other heat softenable or heat set materials used for bonding, forming, etc. Furthermore, the present invention provides a band-shaped heater that functions as a self-adjusting heater, which is wrapped around a single article to be heated or multiple articles to be heated simultaneously are wrapped and fixed together. , and then actuating the heater and maintaining the tension in the band heater substantially constant during the heating period or, if necessary, during the cooling period that follows. be. DESCRIPTION OF THE PREFERRED EMBODIMENTS Another embodiment of the present invention provides a structure that increases the flexibility of a band heater and simultaneously increases its minimum resistance, thereby increasing the flexibility of the heater band. It is an object of the present invention to provide a structure that facilitates impedance matching of the power supply and also allows heat to be confined to only the area where the heated object is in contact with the heater. First, regarding flexibility, band-shaped heaters with a structure in which a central copper core is surrounded by an insulating layer, a high magnetic permeability material is covered, and this is further covered with copper, are quite rigid. Become something. Here, if the high magnetic permeability material is attached in the form of a flat strip only to one surface of the center conductor (for current feedback), and the opposite side of the center conductor to the side on which the high magnetic permeability material is attached, By forming a plurality of slots in the surface of the outer copper conductor layer disposed in the band-shaped heater, the slots are spaced apart from each other by a predetermined distance and extend in a direction perpendicular to the longitudinal direction of the band-shaped heater. The flexibility was found to be significantly increased. Furthermore, the slot limits the current to a smaller area (at least 50%) compared to an unslotted heater and increases the resistance of the band heater, thereby increasing the constant current for the band heater. This has the effect of greatly facilitating power source matching. Also, by limiting the current to only those areas of the outer conductor that are in contact with the high permeability material, heat generation is limited to those areas. Note that the shape of the heater can be changed according to various prior art applications or patents previously filed or patented.

[Brief explanation of drawings]

The above objects, features and advantages of the present invention as well as other objects, features and advantages will become more apparent from the detailed description of specific embodiments set forth below with reference to the accompanying drawings. Dew. FIG. 1 is a partially cutaway perspective view of an embodiment of a band-shaped heater of an automatically adjustable heater according to the present invention, and FIG. 2 is a locking device suitable for use in the band-shaped heater shown in FIG. 1. FIG. 3 is an explanatory diagram showing how the overlapping shield wires of two cables are soldered using the apparatus shown in FIG. An explanatory diagram showing a modified embodiment of the band-shaped heater shown in Fig. 5 (however, the current return path in Fig. 1 is also necessary in this embodiment, but is omitted in the figure). FIG. 6 is an explanatory diagram showing a modified embodiment of the locking device shown in FIG. 2; FIG. 7 is an explanatory diagram showing an embodiment in which the band-shaped heater shown in FIG. Fig. 8 is an explanatory diagram showing a tightening tool modified for use in the system; Fig. 8 is an explanatory diagram showing a state in which force is applied to tighten a band-shaped heater using the tool shown in Fig. 7. FIG. 9 shows a configuration of another type of locking device, in which band-shaped heaters are arranged parallel to each other and their ends are connected to each other so that a grounded current can pass through the heater without the need for a return path. 10 is a front view thereof, FIG. 11 is an explanatory view showing a sleeve for locking the band heater having the tooth profile shown in FIG. 10, and FIG. 12 is an induction heating FIG. 13 is a sectional view showing a part of the band heater shown in FIG. 12 in detail; FIG. 14 is the above-mentioned FIG. 15 is a detailed sectional view showing another embodiment of the induction heating type band heater; FIG. 16 is a perspective view of a tool used when using the induction type band heater; FIG. A perspective view showing a preferred embodiment of the heater. FIG. 17 is a sectional view taken along line 17-17 in FIG. 16. Referring first to FIG. 1 of the accompanying drawings, one form of a band-shaped heater 10 is depicted on a greatly enlarged scale. The band-shaped heater has a bus 1 for current feedback with high conductivity, and its three sides and approximately half of the remaining side are
It is coated with a thin layer 2 of high temperature insulation, such as Kapton tape, 0.001 inch thick. In this embodiment, an exposed surface 3 is formed above the generatrix 1. A layer 4 made of a material of low resistivity, such as copper, for example, and alloy 42 (a ferromagnetic alloy consisting of 42% Ni and 58% Fe. Since the Ni content is 42%, A layer 5 made of a material with high magnetic permeability, such as "Alloy 42" and well known to those skilled in the art), is formed by an adhesive layer 6. It is adhered to the surface of the Kapton tape 2 opposite to the surface 3 of the bus bar 1. The combination of layers 4 and 5 forms a heater structure as described above. As shown in FIG. 1, the lower surface of layer 4 is provided with a layer 8 of a desired material. If it is necessary to remove the band heater after heating operation,
Layer 8 is made of a thin layer with high temperature insulation properties, such as Kapton. Such a layer serves to increase the time required to heat the object to the desired temperature. Alternatively, if the band heater is to be made a permanent part of the structure of the object to be heated to increase its strength, layer 8 may be made of solder, mastic, adhesive, or the like. If layer 8 is a less conductive material, layer 8 is made slightly shorter at the end of the tape to allow electrical connection to layer 4 of the heater. Connections to layer 1 are made at its surface 3. layer 1, 4
and 5 are all connected together at the other end remote from the end where they are connected to the power source. To do this, layers 2 and 6 may be removed and the materials may be soldered or spot welded together, or they may be joined with a conductive mastic or adhesive. Layer 8 is preferably covered by a strong, thin cover 9 made of metal to protect the electrical circuit elements from grabbers 72 as shown in FIG. Referring now to FIG. 2 of the accompanying drawings, the locking device 12 is shown attached to the band-shaped heater 10. As shown in FIG. The locking device 12 is comprised of a tapered housing 14 and a ball 16, and is fixed near one end of the band-shaped heater. In use, one end 18 of the band-shaped heater on the opposite side to the side on which the locking device 12 is attached.
is inserted into the device 12 so as to pass under the ball 16. When one end 18 of the band-shaped heater is moved from the left to the right in FIG. 2, the ball 16 moves to the right, allowing the band to pass freely. However, when trying to move one end 18 of the band-shaped heater from the right side to the left side,
Since the ball 16 moves from right to left and receives a downward force, the band-shaped heater is pressed between the ball and the bottom surface of the device 12. Due to this pushing action of the ball, one end 18 of the band-shaped heater is prevented from moving further to the left. In order to prevent a short circuit at the current input end of the band heater, the ball 16 is made of a non-conductive material. Specifically, the device 12 is often made of metal due to its nature, and this
It is in contact with layer 8 or layer 4 of the band-shaped heater shown in the figure. Therefore, if the ball 16 were made of metal, a short circuit would occur in the device 12 and no current would be supplied to the heated portion of the band heater 10. The layer 5 of high magnetic permeability is interrupted near the device 12, so that little heat is generated in the area between the device 12 and the point where the current is supplied. The apparatus shown in FIG.
It is depicted as a heater of the type disclosed in No. 4,256,945. As previously mentioned, various types of heaters such as those described above are possible. Furthermore, the insulating member may completely cover the upper surface of the layer 1. In that case, either open a window in layer 2 to connect a connector for supplying current, or leave a short break in layer 2 at the end of the tape so that current can be supplied. It is something. If layer 8 is a solder or a thermally adhesive material other than solder, the band heater will remain a permanent part of the final structure. Such an example is shown in FIG. 3, which shows the connection of the shield wire 30 of the first cable 20 to the shield wire 28 of the second cable 22. After connecting the center conductors 24 and filling the cap between them and the insulating layer 26, the shield wire 28 of the cable 22 is pulled over the shield wire 30 of the cable 20. After that, a band-shaped heater 10 as shown in FIG.
is attached around the area of the cable where the braided shield wires 30 and 28 overlap. The end portion 32 of the band-shaped heater 10 is connected to an AC power source 31 with a constant current until the solder layer 8 melts. When the current is cut off and the solder is allowed to cool, the band heater is bonded to the braided shield wire 28, and the shield wire 28 is bonded to the shield wire 30. Thereafter, the end portion 32 of the band-shaped heater 10 is cut, and the work is completed. The above device has several noteworthy features. That is, first of all, the above-mentioned band-shaped heater is not physically limited in its dimensions, and can be commercially available in long lengths, such as 50 feet, 100 feet, etc., rolled up. The user is
Purchase the desired number of locking devices, cut the band-shaped heater to the required length, and use it.
One locking device can be attached and used the next time the band heater is used.
The locking device may include separate tooth areas for penetrating the band heater and shorting the copper layers together. Other means for shorting the layers may include clips, staples, etc. It is also important that the band heater must be appropriately dimensioned to ensure efficient coupling of power from the power supply to it. In order to form a circuit with appropriate impedance matching between the band heater and the power source, the cross-sectional dimensions of the band heater, the length and frequency of the band heater, and the resistivity of the magnetic material used must be adjusted. It needs to be precisely designed depending on the magnetic permeability and also the resistivity of the non-magnetic material, etc. Another feature of the present invention is that the band heater as shown in FIG. 1 can be reused. That is, the band-shaped heater can be peeled off from the object to be heated while the solder is still hot. Such a method of use is particularly possible when the solder permeates into the knitted object to be heated and the permeated solder is not affected even if the band-shaped heater is peeled off. Alternatively, the same can be said of materials that are melted by a band-shaped heater, such as plastics or heat-sealable tapes used for cable repairs. Another important feature of the band heater is due to its basic shape. That is, a band heater such as the one described above can be attached to a cable, pipe, or the like from the side, and can be slipped off the end of the cable or pipe before connecting it. The point is that there is no need to fit it in. Another alternative construction is shown in FIG. 4 of the accompanying drawings. In this embodiment, layer 8 is an insulator that rises along the sides of layers 4 and 5 to prevent solder from contacting layers 4 and/or 5.
In this embodiment as well, the current feedback path shown in FIG. 1 is necessary, but is omitted from the diagram. In this configuration, the solder is applied as a ribbon before the band heater 10 is attached to the heated object, such as the braided shield wires 28 and 30 (see FIG. 3) stacked on top of each other. In this form, the band-shaped heater 10 can be removed from the object to be heated by moving the ball 16 as shown in FIG. 2 toward the right. A hole may be provided in the upper surface of the locking device 12 through which a sharp tool may be inserted to move the ball when removing the band heater. FIG. 5 of the accompanying drawings shows a further different form of the band heater. Reference number 4
In this embodiment of the band heater shown at 8, the current return bus bar is located at the center of the band heater structure. Specifically, the current feedback bus bar 34 is surrounded by an insulating layer 36. A layer 38 of copper is aligned with a ferromagnetic material 40 having a desired Curie temperature, and surrounds three sides of the layer 36, with a portion 43 extending over the top surface of the band-shaped heater from the opposing sides. It is surrounded so that it extends slightly. Another copper layer 44 is positioned to cover the top surface of layer 36 and underlie portions 43 of layers 38 and 40. In the above embodiment, the entire outer peripheral surface of the band-shaped heater having the above structure has the same potential, and therefore the short circuit problem is solved, so that the ball 16 of the locking device
does not have to be metal. Similar to the configuration shown in FIG. 1, the ends of layers 34 and 38 opposite the power source are connected to each other and
A locking device, such as locking device 12 shown in FIG. 2, is installed. In this embodiment, one end of the band heater remote from the point of attachment of the device 12 is passed over the ball (see FIG. 6) and a tool is attached to the end 50 of the band heater 48. can be passed through relatively easily. Preferably, the layers 36 and 43 have large openings near the end 50 of the band heater 48 so that the electrodes of the power supply can contact the layer 34. Referring now to FIG. 7 of the accompanying drawings, there is shown the essential parts of a Panduit installation tool 52 that has been modified for use with the system of the present invention. The tool has an immovable front plate 54 extending forward from a back plate 56 of the tool 52. The front plate 54 also has a slot 58 for receiving the band-shaped heater.
A member 60 having an inclined surface 62 at the right end in FIG. 7 is fixed to the right side surface of the front plate 54. As shown in FIG. When using the above-mentioned tool, the slide member 64 is moved to the right from the state shown in FIG. It extends forward from the back plate 56 of the tool between. The slide plate is actuated by a trigger not shown in the figure. A grip 66 is attached to the slide member 64 near its left or front end, which fits into a slot provided in the slide member 64 and is rotatable about a pivot pin 68. is attached to. The above grab metal 6
The left side surface 70 of the member 6 is inclined so that the left side surface 70 of the member 6
0 surface 62. The right end of the grip 66 has an upwardly extending portion 72 having teeth on its upper surface. The grip is spring-biased to rotate counterclockwise in the figure, so when the slide member 64 is pulled and the grip 66 is moved to the right, the upper surface 70 of the grip is rotated counterclockwise in the figure. The grip is rotated counterclockwise so that the teeth on its elongated end 72 are rotated toward a plate 74 that extends over and moves with the top of the grip end 72. It will be done. The plate 74 is also fixed to the slide member 64. Referring to the upper part of FIG. 8, the operating state of the tool is shown with the band-shaped heater captured between the grip 66 and the plate 74. The lower part of FIG. 8 shows a state in which the band-shaped heater is pulled together with the slide member by moving it to the right, and the band-shaped heater is pulled by moving the slide member to the left. When loosening, a locking device 12 shown in FIG. 6 prevents the band-shaped heater from slipping. Surface 62 of member 60
The grip is rotated clockwise by the cam action and displaced to the position shown in FIG. 7, whereby the tool is easily moved to the left along the band-shaped heater, and then This is brought into position to tighten it even more. Tools configured as described above are available on the market today. In order to utilize the tool in the present invention, the member 74 is provided with a relatively strong insulating layer 76 on the surface facing the end 72 of the grip.
will be provided. Electrical contacts 7 on the insulating layer 76
8 may be provided, in which case the contact point is connected to one terminal of a constant current power source 31 as shown in FIG. 3 through a lead 80. The tooth-shaped portion of the grip 72 is insulated from the slide member 64 and connected to a second terminal of a constant current power source through a lead 82. When using the system, the heater band 10 is wrapped around the member or members to be tightened and heated, and the tail 18 of the heater band is inserted into the slot 58 of the tool.
and into the tool between the plate 74 and the end 72 of the grip. Then, use the tool to tighten the band-shaped heater and turn on the power source. If the band heater becomes loose due to melting or fluidization of the sealant or plastic or the like, the tool is operated again to maintain the band heater tightly tightened. Of course, sufficient pressure must be maintained on the tool's actuation mechanism so that the end 72 of the grip engages the band heater and presses it against the electrode 78. be. Note that it is not necessarily necessary to conduct current to the band-shaped heater through the tool,
Alternatively, there is no need to conduct current at the clamped position as described above. That is, an independent power supply may be used, or a tool may be used that makes electrical connection at a location other than the meshing portion. As shown in FIGS. 9 and 10 of the accompanying drawings,
In another type of band heater, the band heater has an electrically U-shaped configuration. As shown in FIG. 10, a high permeability layer 92 is provided on the top surface of an insulating substrate 90, and a copper or similar layer 94 is provided on the high permeability layer. If the band heater is long enough to require balanced excitation at the contact points,
That is, if the voltages at the contact points must be equal to each other opposite to ground, then a balun transformer may be used to connect the heater to an unbalanced shielded cable, such as a coaxial cable. It becomes necessary. However, if the band-shaped heater is extremely short compared to the wavelength, either contact may be connected to ground, that is, to the shield wire of the cable, without using the balun transformer as described above. Of course, the above structure can also take other forms; for example, two U-shaped heaters may be provided in which the ends of two parallel strips are connected to each other, and the ends of the strips adjacent to each other may be connected to each other. It is also possible to construct a device with four parallel strips connecting the sections. Such a device would further increase its electrical length, and would be approximately twice as long as that shown in FIGS. 1 or 9. Therefore, for a 1 inch cable, the electrical length of the band heater with two U-shaped configurations is
4π, or approximately 12.6 inches. The insulating substrate 90 of the heater shown in FIG. 9 also serves as one member of the locking device, and the outer edge of the insulating substrate 90 has a plurality of cut portions 96 each having an inclined surface and a right-angled surface. is formed.
On the other hand, FIG. 11 shows a locking device 98 that is combined with the insulating substrate 90 to achieve a locking function. The locking device 98 consists of a hollow rectangular sleeve 100,
This includes one or more pairs of resilient inwardly facing tongues 102 and 103 attached to the sleeve 10.
They are provided opposite each other on narrow vertical wall surfaces 104 and 106 of 0, respectively. Therefore, although the heater shown in FIG. 9 can be easily inserted from the right side to the left side of the sleeve 100,
When an attempt is made to move the tongues from the left side to the right side, the tongues 102 and 103 catch on the vertical wall surface of the cut portion 96 of the member 90 shown in FIG. It has become impossible to pull out the band-shaped heater unless it is moved towards the end. In the conventional configuration, the power source was directly connected to the band-shaped heater.
On the other hand, FIGS. 12 and 13 show an example of a modification to a band-shaped heater that heats by induction as an embodiment of the present invention. The heater consists of a strip-shaped layer 110 made of a material with relatively high magnetic permeability and an outer thin insulating layer 112. In this case a locking device 114 as shown and described in FIG.
is used, but unlike the case in Figure 2,
The locking ball 123 is made of a conductive material to short the circuit so that the circulating current can flow. If desired, a solder layer 116 may be added to the layer 110 between the ends of the locking device 114.
It is provided so as to extend over the entire inner circumferential surface of the. The band heater is mounted around a cable or the like as previously described and is a conductive conductor connected via post members 120 and 122 to an AC power source 124 having a predetermined frequency. It is adapted to be heated by a discontinuous flexible wrapping body 118 made of a flexible material. Post members 120 and 12
2 are attached to the ends of a pair of pliers or clips 126 as shown in FIG. 14 of the accompanying drawings. In use, the band heater 108 is wrapped such that its solder layer contacts, for example, a braided shield of a cable. Later, the 14th
The tool shown in the figure is attached in such a way that the clamping body 118 is spread out with its clip open.
The wrapped body 118 is the band-shaped heater 10
8, the clip is tightened until the wrapper 118 is secured around the band-like heater 108, and then a current is applied. In that case, the induction action heats the band heater 108 to its Curie temperature, at which point the layer 11
The magnetic permeability of the zero material is reduced and the current spreads inside the layer, thereby reducing the resistance. Parameters such as current, surface area, resistance, etc. are such that when the temperature is above the Curie temperature, the heat dissipated into the atmosphere reduces the temperature of the band heater to below the Curie temperature, thereby achieving an automatic regulation function. Each is selected as follows. Therefore, in the present invention, it is also possible to employ various different configurations of the earlier application. For example, as shown in FIG. 15 of the accompanying drawings, the copper layer 130 and the ferromagnetic layer 128 can be stacked together. In that case, an insulating layer 132 and a solder layer 134 are also provided as before. In use, as the Curie temperature is approached, current spreads from the high resistance layer 128 to the low resistance layer 130, thereby achieving a self-regulating function. The above-mentioned band-shaped heaters are quite thin, and for example, the band-shaped heater shown in Fig. 1 is used for soldering copper pipes of about 11/2 inches to 2 inches. In this case, the thickness is about 0.018 inches, and the width is about 0.180 inches. The copper and/or alloy 42 or other selected material is of sufficient strength to permit effective tightening. Using a band heater as described above operating at 250 watts, a copper coupling could be soldered onto 11/2 inch copper pipe in one minute. Increasing the energy to 500 watts reduced the time to 20 seconds. It was observed that at around 300 watts, the time is substantially reduced and the load becomes less heat sink than an infinite heat sink near the energy level of the structure defined above. . The present invention provides a unique and complex heater and band device to accomplish the many functions needed to hold a heated object tightly and heat it to a precise temperature. FIG. 3 shows a specific example of the use of the device according to the invention, namely for connecting braided shielded wires stacked one on top of the other, or for connecting braided shielded wires stacked one on top of the other in the form of a connector. Examples are given where the superimposed parts are plastic tubes to be bonded together, copper pipes and/or parts to be bonded, or where a band heater for grounding is attached to a cable. There is no big difference in the basic operation when soldering or heating glue, mask, adhesive, flux, etc. The band-shaped heater may be part of the final structure of the heated object, or may be removed. If the final structure is to be formed, the band heaters serve as reinforcing elements for the finished product, increasing its strength. The band-shaped heater as described above can also be used as a type of heater. Since the above band-shaped heater can be attached from the outside of the object to be heated,
Attach it to the outer surface of a frozen part of a pipe,
Alternatively, it can be used by wrapping it in a spiral around a pipe to heat and thaw the contents of the pipe, to accelerate chemical reactions, or for various other purposes. The structure of the locking device 12 shown in FIG.
It is particularly recommended for permanent attachment to band heaters because of its extremely small size (1/4 inch wide, 3/8 inch long, and approximately 1/4 inch high) Although the structure is
The structure of the locking device can also take various forms. For example, locking devices such as those shown in Figures 9 and 11 are also effectively used in many situations, and can be used for a long period of time after the installation to the band heater is completed. It is strongly held on the band-shaped heater. Reference is now made to FIGS. 16 and 17, which illustrate one preferred embodiment of the present invention. The conductor 136 for current return is the insulating layer 1
It is surrounded by 38. A layer of high magnetic permeability material 140 is provided only along the lower surface of insulating layer 138, which is shown on both sides. A copper layer 142, constructed as described above, forms the outer layer of the device.
surrounded by. Copper or other highly or moderately conductive material 142 is separated by slots as shown at 144. The slot 144 may be provided across the top surface of the band-shaped heater, or may be provided on the top and bottom surfaces, depending on the power source impedance, desired flexibility, etc., as shown in FIGS. 16 and 17. The latter case is shown. The slot 144 serves to limit the flow of current to regions 146 and 148 that are not slotted, that is, in the illustrated embodiment, regions 146 and 148 that are adjacent only to the high permeability layer 140. It is something that we fulfill. As shown above, the current is thin copper layer 1
46 and 148 substantially increases the overall resistance of the device, which facilitates matching the impedance of the current to the heater. On the other hand, slot 14
The flexibility imparted to the heater by 4 allows the band-shaped heater to be wrapped around the object to be heated and tightened tightly around its entire area, thereby making it possible to avoid irregular shapes. This makes these operations substantially easier than with rigid, non-slotted heaters, in that it provides flexibility for use with existing heaters. High permeability layer 140 may be a single layer as shown, or may be a layered structure on a substrate made of copper or other materials. An interesting feature in such a configuration as described above is that the slot 144 confines the current to regions 146 and 148 of the outer conductor layer. Therefore, heat is transferred to the layer 140 of high permeability material.
Occurs only in the above areas that include. Therefore, heat is generated in the immediate vicinity of the heated object, and the heat-generating part, that is, the part made of high magnetic permeability material, is made of conductive material,
It will be separated from the heated body only by a thin layer of copper, stainless steel, or other material with the desired electrical and physical properties of the heated body. Thus, the heater constructed as described above has great flexibility, and the band-shaped heater shown in FIGS. 16 and 17 is particularly suitable for use at frequencies between 8 and 20 MHz due to its high resistance. In some cases, it is easier to match the power source than other types of devices, and it operates more efficiently. The frequency of the power supply used here is not limited to a specific frequency range. 1000 to 5000
Operation above the Hz range provides little increase in performance unless frequencies are used so high as to significantly increase the resistance of the first layer. Thus, in this specification, the term "constant current" does not mean that the current cannot increase, but refers to a current that is guided according to the following equation. AI/I<-1/2AR/R Specifically, in order to achieve automatic temperature regulation, the power given to the load above the Curie temperature must be greater than the power given to the load below the Curie temperature. must also be less. If the current is kept constant, the best power regulation ratio will be obtained, except when controlling the power supply by decreasing the current. However,
Automatic regulation is achieved as long as the current is reduced enough to reduce heating. Therefore, when a large power adjustment ratio is not required, the degree of current control can be less restricted and the cost of the power supply device can be reduced. Note that the above equation is derived from the following equation. P=(I+AI) ² (R+AR) Here, P is power, and if we differentiate this P with respect to R, we get dP/dR=I ² +2RI(dI/dR), but for automatic adjustment, dP /dR<0. Therefore, I ² +2RI(dI/dR)<0, and the above equation is derived from this. As explained above, the insulating layer is provided on the inner surface (the surface of the band-shaped heater that contacts the heated body) to prevent the band-shaped heater from adhering to the solder. This effect can also be achieved by using aluminum, titanium, or other materials to which solder does not easily adhere as the outer conductor layer. As mentioned above, the insulator is preferably an organic or inorganic material having appropriate flexibility and heat resistance, and is not wetted by solder. These materials are specifically determined by the heat applied to the material, the type of solder used, etc. The metal example listed above is an example in which solder made of tin-lead is used. Aluminum and titanium are also used for brazing materials and other high temperature solders. It should be noted that those skilled in the art will readily be able to come up with many other modifications and improvements based on the above description. Accordingly, such modifications and improvements are intended to be within the scope of the invention as defined by the following claims.