JPS6020723A - Malfunction detecting and protecting circuit of heat generating tape connected in parallel and series - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The prior art and the present invention will be explained below with reference to the drawings.

The present inventor first proposed a method of connecting two electrodes facing each other in parallel by dispersing a large number of electrical resistance wires over the entire length thereof, or filling them with a resistive material such as carbon powder. Heat-generating tapes with electrode terminals provided diagonally (Patent Application 1987-43.59'7, hereinafter referred to as the invention in Section 1), and two or more of these connected diagonally in series (Special Application No. 581, filed on June 23, 1988, hereinafter referred to as the invention of Section 2).

Figure 1 shows the circuit of a conventional heat generating tape.
Since the two *pole terminals 9 and 9' of the heating tape 8 are on the same side as the power source 3, the current 5.5' per electrode unit length or flowing through the element 2 increases as the distance from the power source 3 increases to 5>5'.
As the temperature gradually decreases, the heat distribution becomes uneven.

In the first invention, as shown in FIG. 2, the electrode terminals 9, ? ′ diagonally (at one end of the length of the heating tape, one electrode,
At the other end, the current 5 is made equal at two points on the tape that are equal in distance from the longitudinal center to the left and right, and the heat generation distribution is determined using the known method shown in FIG. It was made more uniform compared to the original.

As schematically illustrated in FIG. 3, the second invention connects a large number of heat generating tapes 8' according to the first invention in series diagonally to create a longer heated body 1 while maintaining uniformity of heat generation distribution. For example, it was used to heat and insulate pipelines.

Now, if we think back on the characteristics of the heating tapes shown in Figures 1 and 2, one is that the part of the heating element between the electrodes is
For example, even if part 0.5 m of a tape with a total length of 50 m is broken or damaged and no longer generates heat, the voltage between the electrodes will hardly change and the heat generated in other parts will hardly be affected. That's true. Even if such a local inability to generate heat occurs, for example, if the object to be heated is a pipeline, it is characteristic that the pipeline will almost never become unusable.

However, in the second invention shown in FIG.
Damage to the resistive material or part of element 2, disconnection 22
If such an abnormality occurs, the resistance between the electrodes of the heat generating tape 8' will naturally increase, but the resistance between the electrodes of the heat generating tape 8' will naturally increase.
,8'',8''... This means that the flowing current does not change much. In this case, the current flowing through the damaged disconnected portion 22 will flow to the other healthy portion 23, and the temperature of the other portion 23 may rise. As mentioned above, even if the initial disconnection section 22 is 0.5 m long, if the temperature of the other section 23 increases, the life of this section 23 will be further shortened and the disconnection or damaged section will spread.

There is a risk that this phenomenon will accelerate over time.

An object of the present invention is to detect the faulty part at an early stage even if such a damaged disconnection part 22 occurs, and to prevent the fault from expanding.

In the present invention, a large number of electrical resistance wire elements are distributed and connected over the entire length between two electrodes facing each other in parallel, or a resistance material is filled, so that the resistance wire elements or the resistance material are connected to each other. Kamaishi is made up of a plurality of heat generating tape units arranged in parallel and connected in series such that each unit is fed to one electrode at one end of its length and to the other electrode at the other end of its length. In a heating tape consisting of a column circuit, a voltmeter or voltage abnormality can be detected between the ends of the electrodes that are not connected in series at the adjacent ends of adjacent heating tape units, or between the two electrodes of each heating tape. or a relay that short-circuits between these electrodes or between the electrodes when the resistance wire or the resistance substance is broken or damaged, or the parallel series circuit that is provided with a terminal to which these can be temporarily installed. This article focuses on a good heat generating tape.

One aspect of the present invention, as shown in FIG. 4, is a heat generating tape unit 8', an EF
, 8"-..., etc., a protective relay 12 or 13.13' is provided in the series connection gap 11. For example, the protective relay 12 is connected to the heating tape unit 8'.
, 8", terminals 14, 15 are provided between the terminals, and the electric wire 1 is connected between these terminals.
9 is connected.

Then, suppose that four heating tape units 8', 8'', and 81 are connected in series, and the voltage between electrodes 9 and 9' is 4.
0. If OV is the individual heating tape unit B/,
Between electrodes 1 and 1' such as B# and 8///: tJijIf there is no damage or disconnection, the voltage will be approximately 100V, so the voltage between terminals 14 and 14.
15, that is, the voltage applied to relay 12 is approximately 20
It becomes 0V. However, in the unlikely event that the 8′ heating tape unit
If an abnormality such as disconnection or damage occurs in the relay 12, the voltage between the electrodes 1 and 1' increases to more than 100V, and therefore the voltage applied to the relay 12 also increases. Therefore, this voltage abnormality activates the relay 12 to issue an alarm, for example, so that the disconnection or abnormality 22 can be discovered. The relay 12 in Fig. 4 is connected to terminals 14 and 15 of adjacent tape units.
However, this is not the only case; instead, it may be taken out from the electrodes 1', 1'' of each heat generating tape unit and between the electrodes 1'', 1', such as the relays 13 and 13'. That is, it is also possible to take them out from between the terminals 16.18 and 18.17 and connect them with the connecting wires 20.20' and 21, respectively. If the relays 13, 13' are operated by the voltage difference between the two electrodes of each heat generating tape unit in this way, it will be more accurate than the case of the relay 12.

The operation of the relays 12, 13, 13', etc. is not only to warn of abnormal voltage distribution as described above, but also to alert the terminal 14. It is also possible to provide a function to short-circuit between 15 and 17 and 18. In this case, the heating tape units 8' and 8'' are in parallel, and the electrodes 1.1' may be short-circuited as in the relay 13, but in this case the heat generation of the 1' tape unit 8' is zero. Even if it falls down, it should be placed between adjacent terminals 14 and 15 across the gap 11, or between both electrode terminals of the heating tape unit (between 16 and 18 and between 1
By providing a protective relay between the electrodes (between 8.17), it is possible to prevent the spread of an accident due to disconnection or damage to the resistance element 2 between the electrodes or the filling resistance material.

Note that the term "gap 11" is for convenience's sake, and simply means that one of the electrodes 1 or 1' of the adjacent heating tapes and the resistance wire or resistance material are electrically disconnected at this portion.

Furthermore, there is no need to constantly install abnormality detection/protection relays 12, 13, 13', etc., and tests are only carried out by measuring the voltage or temporarily installing relays between these terminals several times a year. In some cases it may be sufficient. In such a case, it is sufficient to install terminals 14, 15, 16, 17, 18, etc.; the presence of these terminals makes it easier to locate the location of the abnormality in the event that an abnormality occurs; The heating pipeline is longer than 500 baits, and the heating tape unit 8',
When 8"...... are each 50m, the location of the abnormality can be found with an accuracy within 50cm, saving time and materials for repair. .

It is unnecessary to explain that this kind of thing is impossible with a system that supplies power only from one end, such as the known heat-generating tape shown in FIG.

In the above explanation, the damage 22 was explained as a wire breakage, but most of the damage is usually a wire breakage. However, even if the damage is a short circuit, it goes without saying that a heavy pressure abnormality will occur between terminals 14 and 15 or between terminals 16 and 18;

[Brief explanation of drawings]

Fig. 1 is an equivalent circuit of a known heat generating tape, Fig. 2 is an equivalent circuit of a diagonally fed heat generating tape, and Fig. 3 is an equivalent circuit of a heat generating tape formed by connecting diagonally fed heat generating tape units in series.
FIG. 4 is an equivalent circuit of the heat generating tape of the present invention. In these drawings, the numbers represent the following: 1.1' is the electrode of the heating tape, 2 is the resistance wire element or resistance material, 3 is the AC power supply, 4 is the lead wire for connection, 5.5' is the electric wire in the element, 9' is the electrode terminal, 1
1 is the gap between unit heating tapes, 12.13.13' is a protection relay, 14. 15.16.17.18 is connection terminal, 19,2020'
, 21 is a connecting wire, and 22 is a disconnection or abnormality in a resistance element or resistor. For the above patent applicant Chisso Engineering Co., Ltd. 11? Ozusu procedure amendment Written April 1980//day L Display of $ 1988 Patent Application No. 128669 2 Title of invention Abnormality detection/protection circuit for heat generating tapes connected in parallel and series &
Mediation with the case of the person making the amendment Patent applicant Chisso Engineering Co., Ltd. 4, agent No. 15, 4-104, Tsukiji, Chuo-ku, Tokyo (〒1o4) a Date of the Senji old ordinance (voluntary amendment) a Increased due to amendment No number of inventions, Detailed description of the invention in the specification to be amended (a) Contents of the amendment (1) After "Patent Application 1978-" on page 2, line 14, rl1
Insert 3438J. (2) After “1,1′” on page 6, line 12, “,1′,”
Insert 1″′. (3) On the fifth line from the bottom of page 7, after “14.15”, “
Insert ``. (4) In the second line from the bottom, ``will become parallel and'' will be corrected to ``The heat generation of will be zero.Also.'' (5) “I am doing” at the end of the same line means “I am able to do it”
Correct to. (6) Insert "line" next to "resistance" on page 8, line 6. (7) Delete "l or 1'" in line 10.11.

Claims (1)

[Claims] A large number of electrical resistance wire elements are distributed and connected over the entire length between two parallel opposing electrodes, or a resistance material is filled so that the resistance wire elements or resistance materials are parallel to each other. A parallel series circuit is formed by connecting a plurality of heat generating tape units in series such that each unit is fed to one electrode at one end of its length and to the other electrode at the other end of its length. In the heat-generating tapes, a voltmeter is used to detect voltage abnormality between the ends of the non-series connected electrodes of adjacent ends of adjacent heat-generating tape units or between two electrodes of each heat-generating tape. When the relay or the resistance wire or resistance material is disconnected or damaged, between these electrodes or 't%T,
Install a relay that shorts the poles or temporarily replace them.