JP6840521B2 - Heater device - Google Patents

Description

The present invention relates to a heater device, and more particularly to a heater device capable of enabling rapid and stable temperature rise and performing more precise temperature control.

A cartridge heater is known as one type of heater device (see, for example, Patent Document 1). The cartridge heater has a structure in which a rod-shaped electrically insulating core (insulator) in which a heating wire is wound around the outer peripheral surface is housed in a metal tube with an electrically insulating powder interposed therebetween. The connection terminals at both ends of the heating wire are provided on one end side of the metal pipe. Since the cartridge heater uses a relatively thin heating wire, the power density on the surface of the heater is relatively low. Since the heating wire is arranged in the vicinity of the metal tube, it is advantageous for rapidly raising the temperature of the heater surface. On the other hand, due to the heat capacity of the electrically insulating core, the temperature rise inside the electrically insulating core is slower than that of the metal tube. Therefore, it takes a considerable amount of time to stabilize the temperature of the entire heater.

As another type of heater device, a sheathed heater is known (see, for example, Patent Document 2). The sheathed heater has a structure in which a coiled heating wire is embedded in an electric insulator at the center of a metal tube. Since a relatively thick heating wire can be used in the sheathed heater, the power density on the surface of the heater is relatively high. In the sheathed heater, since the temperature rises from the inside of the heater, it is possible to raise the temperature of the entire heater quickly and stably. However, it is difficult to control the temperature of the heater surface in detail.

Japanese Unexamined Patent Publication No. 7-192858 Japanese Unexamined Patent Publication No. 6-89776

An object of the present invention is to provide a heater device capable of performing rapid and stable temperature rise and more precise temperature control.

In order to achieve the above object, the heater device of the present invention is a heater composed of a metal tube and a plurality of heating wires extending in the longitudinal direction of the tube with an electric insulator interposed inside the metal tube. and parts, and a controller for individually controlling the power supply to the plurality of heating wires, and the plurality of heating lines are arranged at different distance from the inner peripheral surface of the metal tube , The wire diameter of the heating wire arranged at a position where the separation distance is relatively large is set to be relatively large, and the electric resistance value is set to the heating wire arranged at the position where the separation distance is the smallest. A detection heating wire whose temperature dependence is higher than a predetermined reference is used, and a sensor for detecting the electric resistance value or the current value of the detection heating wire is provided, and the detection data by the sensor is input to the control unit. The electric resistance value or the current value of the detection heating wire at the time of steady heating is grasped in advance, and the grasped appropriate range of the electric resistance value or the current value is input to the control unit. Based on the comparison between the electric resistance value or the current value of the detection heating wire detected by the sensor and the electric resistance value or the current value in the appropriate range, the control unit causes the abnormal overheating of the heater unit. It is characterized in that it is configured to control to de-energize all the heating wires when the presence or absence is determined and it is determined that the heating wire is abnormally overheated.

According to the present invention, a control unit can independently energize a plurality of heating wires arranged at different distances from the inner peripheral surface of the metal tube. Energizing the heating wire arranged at a position where the separation distance is small is advantageous for finely controlling the surface temperature of the heater portion. On the other hand, energizing the heating wire arranged at a position where the separation distance is large is advantageous for quickly and stably raising the temperature of the entire heater section. Therefore, by appropriately setting the selection of the heating wire to be energized and the timing of energizing the heating wire, it is possible to raise the temperature quickly and stably, and to perform more precise temperature control.

It is explanatory drawing which schematically exemplifies the heater device of this invention. It is explanatory drawing which illustrates the inside of the heater part of FIG. It is a view of arrow A of FIG. It is a graph which illustrates the temperature control in the heater device of FIG. It is explanatory drawing which schematically exemplifies another embodiment of a heater device.

Hereinafter, the heater device of the present invention will be described based on the embodiments shown in the drawings.

The heater device 1 of the present invention illustrated in FIG. 1 includes a heater unit 2 and a control unit 8 for controlling the temperature of the heater unit 2. The heater unit 2 includes a metal tube 3, a plurality of heating wires 5 and 6 extending in the longitudinal direction of the metal tube 3, an electrically insulating core 4 housed inside the metal tube 3, and an electrically insulating powder. It is composed of 7. Each of the heating wires 5 and 6 is connected to the power supply 9 via the control unit 8. In this embodiment, the heater device 1 has two heating wires 5 and 6, but it is also possible to have a specification having three or more heating wires.

The material of the metal tube 3 is selected from, for example, stainless steel, aluminum, copper, iron, titanium, etc. according to the heating temperature range and the application. As the electrically insulating core 4, for example, a sintered body of magnesium oxide is used. The electrically insulating core 4 has, for example, an outer diameter of about 10 to 32 mm and a length of about 100 to 300 mm. The heater portion 2 can be lengthened by connecting a plurality of electrically insulating cores 4 in the longitudinal direction.

As the material of the heating wires 5 and 6, for example, nickel / chromium, iron / chromium, and pure nickel are used. The heating wires 5 and 6 may be made of the same material or different materials. For example, magnesium oxide is used as the material of the electrically insulating powder 7.

To elaborate on the structure of the heater unit 2, as illustrated in FIGS. 2 and 3, a rod-shaped electrically insulating core 4 extends in the longitudinal direction of the metal tube 3 inside the metal tube 3. One heating wire 5 is spirally wound around the outer peripheral surface of the electrically insulating core 4, and the other heating wire 6 is arranged inside the electrically insulating core 4.

The electrically insulating core 4 is formed with four through holes 4a penetrating in the longitudinal direction. At one end of the electrically insulating core 4 in the longitudinal direction, connection terminals 5a and 6a are attached to the through holes 4a, respectively.

One end and the other end of one heating wire 5 in the longitudinal direction are connected to the pair of connecting terminals 5a and 5a arranged to face each other, respectively. The heating wire 5 is spirally wound around the outer peripheral surface of the electrically insulating core 4 and extends from one end to the other end in the longitudinal direction of the electrically insulating core 4. At the other end of the electrically insulating core 4 in the longitudinal direction, the heating wire 5 is inserted into the through hole 4a and extends from the other end of the electrically insulating core 4 in the longitudinal direction to one end. As a result, the heating wire 5 forms a loop-shaped first circuit.

One end and the other end of the other heating wire 6 in the longitudinal direction are connected to the other pair of connecting terminals 6a and 6a arranged to face each other, respectively. The heating wire 6 extends through the through hole 4a from one end to the other end in the longitudinal direction of the electrically insulating core 4. At the other end of the electrically insulating core 4 in the longitudinal direction, the heating wire 6 is inserted into the facing through hole 4a and extends through the through hole 4a from the other end of the electrically insulating core 4 in the longitudinal direction to one end. As a result, the heating wire 6 forms a loop-shaped second circuit. Therefore, there are separate and independent circuits for the first circuit and the second circuit.

The electrically insulating powder 7 is filled between the outer peripheral surface of the electrically insulating core 4 and the inner peripheral surface of the metal tube 3. Each of the heating wires 5 and 6 is in a non-contact state with the metal tube 3.

In order to manufacture the heater portion 2, the electrically insulating core 4 in which the heating wires 5 and 6 are arranged is inserted into the metal tube 2 whose one end in the longitudinal direction is closed. Next, the electrically insulating powder 7 is located between the inner peripheral surface of the metal tube 2 and the outer peripheral surface of the electrically insulating core 4, between the through hole 4a and the heating wire 6, and between the through hole 4a and the connection terminal 5a. Fill. Next, the heater portion 2 is integrated by reducing the diameter of the metal tube 2 by swaging or pressing.

In this way, a plurality of heating wires 5 and 6 are housed inside the metal tube 3 with the electrically insulating core 4 and the electrically insulating powder 7 interposed therebetween. The heating wires 5 and 6 are arranged so that the distance d (d1 <d2) from the inner peripheral surface of the metal tube 3 is different. The heating wire 5 arranged at a position where the separation distance d (d1) is relatively small is arranged on the outer peripheral side of the axial center portion of the metal tube 3. The heating wire 6 arranged at a position where the separation distance d (d2) is relatively large is arranged at the axial center portion of the metal tube 3.

Due to the structure, it is difficult to increase the diameter of the heating wire 5 arranged on the outer peripheral surface of the electrically insulating core 4, and it is easy to increase the diameter of the heating wire 6 arranged inside the electrically insulating core 4. Therefore, in this embodiment, the wire diameter of the heating wire 6 arranged at the axial center portion of the metal tube 3 is set to be larger than that of the heating wire 5 arranged on the outer peripheral side of the axial core portion. The outer diameter of one heating wire 5 is, for example, 0.05 mm to 0.35 mm, and the outer diameter of the other heating wire 6 is, for example, 0.1 mm to 1.8 mm. The wire diameter of the heating wire 6 can be about the same as the wire diameter of the heating wire 5, but it is preferably about 300 to 500%.

The heating wire 6 does not have a habit-formed specification formed in a coil shape or the like, but may have a linear specification without habit. However, if the specifications are habitualized, the length of the heating wire 6 that can be accommodated in the metal tube 3 becomes long, which is advantageous for increasing the amount of heat generated.

The control unit 8 individually controls the energization of the heating wires 5 and 6, respectively. Since each of the heating wires 5 and 6 generates heat by energizing electricity from the power source 9, the timing at which the heating wires 5 and 6 generate heat is controlled by the control unit 8. Whether only one heating wire 5 is energized, only the other heating wire 6 is energized, or both heating wires 5 and 6 are energized, the energization of both heating wires 5 and 6 is stopped. It can also be de-energized.

In the heater device 1 of the present invention, the heating wires 5 and 6 arranged at different distances d can be independently energized by the control unit 8. When the heating wire 5 arranged at a position where the separation distance d is small is energized, it is easy to control the surface temperature of the heater unit 2 in detail. On the other hand, when the heating wire 6 arranged at a position where the separation distance d is large is energized, it is easy to raise the temperature of the entire heater unit 2 quickly and stably. Therefore, by appropriately setting the selection of the heating wire to be energized from the heating wires 5 and 6 having different separation distances d and the timing to energize the selected heating wire, the heater unit 2 can be rapidly and stably heated. , It becomes possible to achieve both precision temperature control.

Temperature control when the object is heated in a predetermined temperature range set in advance by using the heater device 1 will be described with reference to FIG.

In FIG. 4, the temperature range sandwiched by the broken lines is a preset temperature range for heating in a steady state. Therefore, until the temperature rises to this predetermined temperature range, the heating wire 6 arranged at least at the position where the separation distance d is the largest is energized. That is, only the heating wire 6 or both heating wires 5 and 6 are energized to generate heat. To maximize the rate of temperature rise, both heating wires 5 and 6 are energized. On the other hand, when the reduction of power consumption is given the highest priority, only the heating wire 6 is energized.

As a result, the temperature of the entire heater unit 2 can be raised quickly and stably, and the object can be raised to a predetermined temperature range at an early stage. Since a large amount of heat is required at this stage, it is preferable that the diameter of the heating wire 6 is larger than that of the heating wire 5.

After the object reaches a predetermined temperature range, the heating wire 6 arranged at the position where the separation distance d is the largest is de-energized, and the heating wire 5 arranged at the position where the separation distance d is the smallest is energized. And control non-energization. At this stage, since the entire heater unit 2 is sufficiently heated, the object can be maintained in a predetermined temperature range only by adjusting the temperature relatively narrowly.

Therefore, the surface temperature of the heater unit 2 can be controlled in detail by repeating the control of energization or de-energization of the heating wire 5 arranged closer to the metal tube 3. This makes it possible to realize steady heating that precisely maintains the object in a predetermined temperature range.

In order to control the surface temperature of the heater unit 2 in detail, it is advantageous that the amount of heat generated by the heating wire is small. Therefore, if the structure uses a relatively small-diameter heating wire 5 wound around the outer peripheral surface of the electrically insulating core 4, it becomes easy to precisely control the temperature of the object.

As described above, the heater device 1 of the present invention utilizes the heating wire 6 (second circuit) arranged inside the electrically insulating core 4 when the temperature is raised, and in the steady state after the temperature is raised, the metal tube 3 is more. The heating wire 5 (first circuit), which is arranged nearby and has excellent responsiveness to temperature, is used, and the first circuit and the second circuit are skillfully combined and used. Therefore, it has realized temperature control that has been difficult to realize in the past, that is, both quick and stable temperature rise and more precise temperature control. In such temperature control according to the present invention, the power consumption of the entire heater unit 2 can be suppressed, so that flicker countermeasures can be taken.

In this embodiment, the connection terminals 5a and 6a of the heating wires 5 and 6 are cartridge heaters arranged at one end in the longitudinal direction of the heater unit 2, but the present invention is not limited to this specification. The specifications may be such that the connection terminals 5a and 6a are arranged at both ends of the heater portion 2 in the longitudinal direction.

When the heater unit 2 is provided with three heating wires, for example, in addition to the heating wires 5 and 6 described above, the heating wires having a separation distance d of d1 <d <d2 are placed in the electrically insulating core 4. Place in. Alternatively, in addition to the heating wires 5 and 6 described above, heating wires having a separation distance d of d2 <d may be arranged in the electrically insulating core 4. In the present invention, the separation distances d of all the heating wires may be different, but at least the separation distances d of the two heating wires may be different.

In another embodiment illustrated in FIG. 5, in addition to the previous embodiment, the sensor 10 for detecting the electric resistance value of the heating wire 5 is provided. The detection data by the sensor 10 is input to the control unit 8. The sensor 10 may be a sensor 10 that detects a current as long as it can detect a change linked to the electric resistance value of the heating wire 5. Further, in this embodiment, a detection heating wire having a temperature dependence of the electric resistance value higher than a predetermined reference is used for the heating wire 5. As the heat generating wire for this detection, for example, a nickel / iron alloy wire or a nickel wire is used. Other specifications are the same as in the previous embodiment.

In this embodiment, the electric resistance value (current value) of the detection heating wire 5 is detected by the sensor 10. Then, the control unit 8 determines whether or not the heater unit 2 is abnormally overheated based on the detected electric resistance value (current value).

For example, the electric resistance value (current value) of the detection heating wire 5 at the time of steady heating is grasped in advance, and the appropriate range of these is input to the control unit 8. Then, when the electric resistance value (current value) detected by the sensor 10 deviates from the appropriate range, it is determined to be abnormal overheating. For example, when the electric resistance value of the detection heating wire 5 becomes larger than the appropriate range, it is determined that the temperature is abnormally overheated. Alternatively, when the current value of the detection heating wire 5 becomes smaller than the appropriate range, it is determined that the heating wire is abnormally overheated.

When it is determined that the heat is abnormally overheated, the control unit 8 controls to de-energize all the heating wires 5 and 6. This is advantageous for avoiding problems due to abnormal overheating. The heating wire for detection can be used for any of the heating wires 5 and 6, but from the viewpoint of quickly detecting the surface temperature of the heater unit 2, the heating wire 5 arranged at the position where the separation distance d is the smallest is used. Good to use. Further, since the electric resistance value of the entire circuit is larger in the thinner heating wire, it becomes easier to detect the change in the electric resistance value. Therefore, it is preferable to use a detection heating wire for the heating wire 5 having a relatively small diameter.

1 Heater device 2 Heater section 3 Metal tube 4 Electrical insulation core (electric insulator)
4a Through hole 5 Heating wire 5a Connection terminal 6 Heating wire 6a Connection terminal 7 Electrical insulation powder (electric insulator)
8 Control unit 9 Power supply 10 Sensor d (d1, d2) Separation distance

Claims (4)

A heater unit consisting of a metal tube and a plurality of heating wires extending and accommodating in the longitudinal direction of the tube with an electric insulator interposed inside the metal tube, and energizing the plurality of heating wires. A control unit for individual control is provided, and the plurality of heating wires are arranged at different distances from the inner peripheral surface of the metal tube, and are arranged at positions where the distances are relatively large. The heating wire for detection has a relatively large wire diameter and is arranged at a position where the separation distance is the smallest, and the temperature dependence of the electric resistance value is higher than a predetermined reference. A wire is used, and a sensor for detecting the electric resistance value or the current value of the detection heating wire is provided, and the detection data by the sensor is input to the control unit for the detection during steady heating. The electric resistance value or the current value of the heating wire is grasped in advance, and the grasped appropriate range of the electric resistance value or the current value is input to the control unit, and the detecting heating wire detected by the sensor. When the control unit determines whether or not the heater unit is abnormally overheated based on the comparison between the electric resistance value or the current value of the above and the electric resistance value or the current value in the appropriate range, and it is determined that the heater unit is abnormally overheated. Is a heater device characterized in that all the heating wires are controlled to be de-energized. The wire diameter of the heating wire arranged at the position where the separation distance is the smallest is 0.05 mm to 0.35 mm, and the wire diameter of the heating wire arranged at the position where the separation distance is the largest is the separation distance. The heater device according to claim 1, which is 300% to 500% of the wire diameter of the heating wire arranged at the smallest position. A rod-shaped electrically insulating core extends in the longitudinal direction of the metal tube, and the plurality of heating wires are spirally wound around the outer peripheral surface of the electrically insulating core, and the electricity. The heater device according to claim 1 or 2, which includes a heating wire arranged inside an insulating core. When heating in a predetermined temperature range set in advance, the heating wire arranged at least at the position where the separation distance is the largest is energized until the temperature rises to the predetermined temperature range, and the temperature is set to the predetermined temperature. After reaching the range, the heating wire arranged at the position where the separation distance is the largest is de-energized, and the energization and de-energization of the heating wire arranged at the position where the separation distance is the smallest is controlled. The heater device according to any one of claims 1 to 3, which is configured to maintain the predetermined temperature range.

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