JPH0410198B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heater bundle in which an electric sheathed heater having electric heating means is installed in a container into which a fluid as a heated object is introduced.

[Prior Art] The electric heater constituting the heater bundle is:
An electric heating element is housed in a metal sheath such as stainless steel, and the sheath is filled with an inorganic insulating material such as magnesia powder or boron nitride powder.
A current is passed through the electric heating element to heat it.

FIG. 5 shows an example of the heater bundle. A plurality of electric heaters 2 are bundled in parallel at intervals with spacers 8 interposed therebetween, and the electric heaters 2 are housed in a container 1. An electric heating element 4 is housed in the sheath 3 from one end to the other, and the electric heat is supplied through individual terminals 5 arranged on the outside of the container 1 and a collective electrode 7 attached to the other end of the container 1. A power source is connected to the heating element 4.

In the heater bundle, in the temperature measuring section 9,
The temperature of the heated water in the container 1 is measured, but in the conventional heater bundle, the large current flowing through the electric heating element 4 in the electric heater 2 causes electrical noise to affect the measurement sensor signal. There was a problem in that temperature measurement was impaired.

Therefore, in order to solve these problems, an electric heater 2 is usually used in which the electric heating element 4 is not passed through the temperature measuring section 9, or the power supply current is not passed therethrough. In this case, the electric heating element 4 is folded back in front of the temperature measuring section 9, and both ends are connected to the container 1.
means for connecting at one end side, or connecting one end of the electric heating element 4 to the sheath 3 in front of the temperature measuring section 9;
A means for connecting to a power source through the sheath 3 which is grounded through the spacer 8 is employed.

In FIG. 5, 10 is a fluid outlet of the container 1, 10a is a tube cover, and 10b is a fluid outlet.

[Problems to be Solved by the Invention] In the former method, two lead wires and terminals must be arranged for each electric heater 2 on one end side of the container 1, resulting in overcrowding of the wires and terminals. For,
It is necessary to increase the arrangement pitch of the heaters, and the diameter of the container 1 cannot be reduced. For this reason, the flow velocity of the fluid to be heated on the surface of the electric heater decreases, resulting in a decrease in heat transfer efficiency, making it impossible to increase the efficiency of the heater. In the latter case, the sheath 3 is interposed between the power source and the electric heating element 4, and since current flows through it and generates heat, an amount of heat greater than that generated by the electric heating element 4 is generated, and the sheath 3 and the container 1 due to the electrical resistance of the sheath 3, which may cause electrical corrosion. That is, since a power supply voltage is applied to the sheath 3, a potential difference is generated between the container 1 and the sheath 3 via a heated fluid such as water, thereby causing electrolytic corrosion.

The present invention aims to address the aforementioned problems with conventional heater bundles.

[Means for explaining the problem] Citing the symbols shown in Figures 1 to 4,
To explain the structure of the present invention, one electric heating element 14 is folded back at the distal end side of the sheath 13 and inserted into the sheath 13 in two strips. One end of the electric heating element 14 is connected to an individual terminal 15 on the outside of the sheath 13 on the proximal end side, and the other end is connected to a connection point 16 on the proximal end side of the sheath 13 that forms the outer shell of the electric heater 12. Connect to. Further, a collective electrode 17 attached to the mouth end of the container 11 is conductively fixed near the connection point 16 of the sheath 13.

[Function] In the heater bundle, only one end side of the electric heating element 14 is connected to the power source via the individual terminal 15 outside the container 11, so that the single electric heater 12
It is sufficient to have one individual terminal 15 for each terminal. The other end of the electric heating element 14 is connected to the collective electrode 17 via the sheath 13.
and the collective electrode 17 are in contact with each other through a slight thickness of the sheath 13 in the container 11, so the sheath 13
Almost no heat is generated due to electrical resistance. Furthermore, almost no potential difference occurs between the sheath 13 and the container due to the electrical resistance of the sheath 13.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a structural conceptual diagram of an electric heater 12 used in the present invention, in which a single electric heating element 14 inserted into a sheath 13 is folded back halfway through the sheath 13, and both ends thereof are folded back. It is arranged on the proximal end side of the sheath 13. Lead wires 20 and 21 are inserted into the proximal end of the sheath 13, and the ends of the electric heating element 14 are electrically conductively fixed to these wires by means such as welding. The electric heating element 14 and the sheath 13 are the sheath 1
3 is insulated by an inorganic insulating material 25 filled in.

One lead wire 20 is pulled out from the base end of the sheath 13 and connected to the individual terminal 15. Further, the other lead wire 21 is connected to the sheath 13 at the connection point 16.
is conductively fixed to the inner circumferential surface of the A taper is formed on the outer peripheral side of the connection point 16 of the sheath 13, and a collective electrode 17 formed of a conductor is fitted and fixed thereto. The individual terminals 15 are connected to the anode of the power source a, and the collective electrode 17 is connected to the cathode of the power source a via ground, thereby allowing current to flow from the power source a to the electric heating element 14.

Such an electric heater 12 is illustrated in FIGS. 2 to 4, for example.
It is embodied as shown and configured as a heater bundle. That is, a plurality of electric heaters 12 are installed in the container 11 via spacers 18. In this case, the electric heating element 14 inside the sheath 13
is folded back in front of the temperature measuring section 19. The collective electrode 17 is fixed to a tube plate 26 that closes the end of the container 11, and the proximal end of the electric heater 12 near the connection point 16 is fitted here, and is grounded through the tube plate 26. . The tube plate 26 may be used as it is for the collective electrode 17. On the other hand, the individual terminals 15 are arranged outside the container 11, and the power supply a
connected to.

In FIG. 2, 30 is a fluid inlet of the container 1, 31 is a tube cover, and 32 is a fluid outlet.

FIG. 3 shows an example of means for fixing the sheath 13 and the collective electrode 17. Here, a tapered joint 22 is joined to the proximal end of the sheath 13, and a corresponding joint part 22 is opened at the collective electrode 17. The joint portion 22 is fitted into the through hole or joined together, and further tightened with a screw 23.

As shown in FIG. 4, the lead wire 21 is electrically conductively fixed to the inner peripheral side of the mouth end of the sheath 13 by means such as welding before the joint portion 22 is joined. This connection point 1
6 and the collective electrode 17 are preferably as close as possible, and in the illustrated embodiment, the collective electrode 17 is fitted in a position very close to the connection point 16. The lead wire 20 is further connected to another lead wire 24 having a larger diameter, and connected to the individual terminal 15 outside the container 11.

[Effects of the Invention] As explained above, according to the present invention, it is sufficient to provide one individual terminal 15 for each electric heater 12, and the sheath 13 in the container 11
It is possible to eliminate galvanic corrosion caused by potential difference. That is, a heater bundle can be obtained in which the size and shape of the container 11 can be selected to appropriately set electric heating conditions, and which can function as a heater without causing electrolytic corrosion of the sheath material.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention, in which FIG. 1 is a conceptual diagram showing the structure of an electric heater, FIG. 2 is a schematic longitudinal sectional side view of a heater bundle, and FIG. FIG. 4 is an enlarged sectional view of section A in FIG. 3, and FIG. 5 is a schematic vertical sectional side view showing a conventional example of a heater bundle. 11... Container, 12... Electric heater, 13...
Sheath, 14... Electric heating element, 15... Individual terminal, 16... Connection point, 17... Collective electrode.

Claims (1)

[Claims] 1. In a heater bundle in which a plurality of electric heaters 12 each having an electric heating element 14 insulated and housed in a metal sheath 13 are attached to a container 11, one electric heating element 14 is folded back inside the sheath 13. , are arranged in two strips in the sheath 13, one end of the electric heating element 14 is connected to an individual terminal 15 on the outside at the base end side of the sheath 13, and the other end of the electric heating element 14 is connected to an electric heater. A collective electrode 17 connected to a connection point 16 on the proximal end side of a sheath 13 forming an outer shell of the container 12 and attached to the mouth end of the container 11 is conductively fixed near the connection point 16 of the sheath 13. and heater bundle.